Dissertation > Excellent graduate degree dissertation topics show
Modeling Severe Skull Base Defect and Exploratory Development on a New Material--Complex of Shape-Memory Alloy Brace and Biomembrane Flap to Skull Base Reconstruction
Author: WangZhiQiang
Tutor: QiSongTao
School: Southern Medical University,
Course: Neurosurgery
Keywords: Skull base reconstruction Biocompatible material Shape memory alloy Artificial dura Leakage of cerebrospinal fluid
CLC: R651.1
Type: PhD thesis
Year: 2012
Downloads: 61
Quote: 0
Read: Download Dissertation
Abstract
Background and Objection:Skull base reconstruction is necessary portion of skull base surgery, which is so difficult because space is narrow and the organizational structure is complex. Bony and membrane structure defect caused by skull base surgery could bring up a lot of complication such as cerebrospinal fluid leakage, intracranial organization shift, and secondary intracranial infection, encephalomeningocele and corresponding disorders of nervous functions. Therefore, reliable reconstruction powerfully guarantees skull base surgery patients to recovery. We should establish a reliable lasting brain barrier, eliminate the dead space, do not affect the disease rechecked, obtain ideal beauty effect and avoid the appearance of the postoperative complications based on the convenient, simple operation, little injury, and true effect.The initial skull base reconstruction was only closing dura mater with skip flap, followed by development of the local flap but with high incidence of CSF leakage and mortality. In1970s, regional myocutaneous flap was used to cure large defect, and osseous reconstruction was attemptted. In the80s and90s with the development of free tissue flap and free tissue flap with blood vessels, the effect of skull base reconstruction is more reliable. Autologous and foreign materials with respective good and bad points were applied parallelly. The autologous materials have been developed toward establishing effective blood, and foreign materials were more and more applied clinically because of good biocompitability, convenience, easily moulding and avoiding second trauma better than the characteristics of autologous material. The techniques of skull base reconstruction in clinical diagnosis and treatment have been developed from simple suturing, leak stopping to multilayer reconstruction and original anatomical structure recovery, from the uncertainty of the repair to unclear cognition of simultaneous the membrane/soft organization reconstruction and osseous reconstruction.Whether in the microscopic neurosurgery or in endoscopic neurosurgery, skull base reconstruction technique make great progress. Since the1990s, many various kinds of means and ways have appeared, according to clinical doctors personalized characteristic. Multilayer reconstruction is widely known and accepted, which used one or several material with sandwich type or any of the improved methods so as to ascertain all the more to avoid postoperative severe complications such as cerebrospinal fluid leakage.Compared with large, abundant and different clinical data, precise and normative experiment research was but relatively low. Most reports in the literature of werere localized, obvious individual results, and had no common representative value.To find a kind of material and method which can be applied to clinical work and deal with different situation of the skull base defect, imagine a kind of complex of shape memory alloy and membrane materials, the former acting as support and the latter acting as the membranous repair function, at the same time which can keep the same shape after stretched out-drawn back and flexed, to synchronously finish osseous and membranous reconstruction. Not only it can reach the clinical effect and more convenient operation and shorten the operative time and trauma, but increase safety coefficient of the treatment.In1963, Buehler, working at the United States naval ordnance laboratory, found that nickel-titanium alloy with equal atom ratio has the shape memory function, and named it after Nitinol which were the abbreviations reflecting the composition and initial found units of ni-ti-navy-ordnance-laboratory.In further study, it was found that Nitinol was a kind of unique to ecological material, which still has excellent biocompatibility, high damping effect, high strength, corrosion resistance, the flexibility, and fatigue resistance, and other features in addition to good shape memory effect. Therefore, Nitinol has been widely used in biomedical fields.Nitinol application in neurosurgery is less and developing at present, only including manufacturing aneurysm clamp, vascular interventional material for treatment, and so on. NormalGEN is a kind of biological artificial dural with completely independent intellectual property rights, has been verified at many experiments and used clinically for repairing dural defects.At this topic, Nitinol and NormalGEN were treated as materials which was designed and manufactured as implants for skull base reconstruction both as osseous reconstruction and membranous reconstruction, corresponding instrument designed in the meantime, which would decrease operative trauma and shorten operative time while not increase patients and medical units operating costs. At the same time, biological toxicity of Nitinol was detected in that it has been reported in recent years that Nitinol may release the nickel ions which has ambiguous biological toxicity.Methods and materials:Chapter1:Design and production of complex of shape memory alloy-membrane flap and its corresponding instrument1. Predetermined schemes:there were three schemes of shearing type, disengaging type1and2, each including shape memory alloy brace and delivering instrument. Detailed structure, composition, operation and chart were not listed.2. Manufacture:According to the predetermined scheme, firstly produce Nitinol brace; secondly produce biological artificial dural with pig tendinous film as material packing Nitinol brace inside. At the same time, make the corresponding instrument.Chapter2:Establishment and experimental treatment of dogs model with middle skull base defect and cerebrospinal fluid leakage1. Experimental animals and grouped:2were randomly chosen to model in7healthy hybrid dogs, and the remaining5randomly numbered and experimentally treated based on modeling, namely Skull base reconstruction followed up modeling with sterilized complex of Nitinol brace-NormalGEN.2. Studied the anatomic characteristics of dog cranial and performed preliminary experiment so as to ensure surgical incision and corresponding surgical approach, foresee possible intraoperative problem, prepare special equipment, and so on.3. Model making:The animals were anesthetized by abdominal-venous composite anesthesia. Breathe by tracheal intubation. Supply continuously hypoflow oxygen. Monitored by ECG, and, when necessary, supported by the ventilator, maintained venous circuit. Fixed and protected at the side position with head high. The adjacent area was skin prepared from eye socket backward to antilobium up zygomatic arch and sterilized with iodophors. The arc incision was about5cm long between the cross point of rear margin of unilateral eye socket with level line and midpoint of zygomatic arch. Cut open skin to lateral bone area of middle skull base. It is mark where Vertical and horizontal bone texture transmigrate, namely, bone transit from horizon to vertical plane for identification. Inside the mark, drill a. bone window about1cm in diameter with high-speed miniature grinding drilling. Radially cut dural open together with arachnoid, confirm brain tissue exposed and cerebrospinal fluid overflow. Stop bleeding reliably and pave the thin layer gelatin sponge on dural. Interrupted and layered suture muscle and fascia. Continuously and intracutaneously suture skin with introversion method. During operation, intravenously inject2.4million units of penicillin within1000ml to1500ml physiological saline containing glucose. Remove tracheal intubation in time. Nursed lonely, bound slightly, eat early liquid diets and keep clean incision. Remove constraint after3days. Keep separately for2weeks. 4. Experimental therapy:The sterilized complex of Nitinol brace-Normal GEN was implanted into epidural gap (namely intracranial-epidural space) in defect area of middle skull base, based on successful modeling and aided by the corresponding instrument. Other disposal of experimental-treated animals was consistent with model animals.5. Observe indexes:Dog’s postoperative activity, the survival condition and whether or not cerebrospinal fluid leakage occurs, etc.; imaging and histopathological examination3months after operation.Chapter3:Establishment and experimental treatment of dogs model with frontal sinus defect and cerebrospinal fluid rhinorrhea1. Experimental animals and grouped:Same as Chapter2definitely.2. Studied the anatomic characteristics of dog cranial and performed preliminary experiment same as Chapter2in principle.3. Model making:Fixed and protected at the side position with head high, mandible adducted and neck lateral flexion so as to frontal region mediate and higher. Triangle hook incision was with two edges, each about2cm long, which angle was about60degree and base toward anterolateral orbital part. One edge was posterolateral margin of unilateral frontal sinus, another was midline. Cut open skin to bone, dissect myocutaneous flap to anterolateral base, expose ipsolateral frontoparietal bone area, drill a bone window about12mm in diameter on prominent place with high-speed miniature grinding drilling, expose and cut open mucous membrane of frontal sinus. Drill a bone window about10mm in diameter on a little even place on inferior wall of frontal sinus close to midline with high-speed miniature grinding drilling, expose and radially cut open dural together with arachnoid, confirm brain tissue exposed and cerebrospinal fluid overflow. Stop bleeding reliably and pave the thin layer gelatin sponge with EC glue on dural. Compress for incision flap moving with breathing. General management was identified with Chapter2.4. Experimental therapy:The sterilized complex of Nitinol brace-NormalGEN was implanted into epidural gap (namely intracranial-epidural space) in defect area of inferior wall of frontal sinus, based on successful modeling and aided by the corresponding instrument. Other disposal of experimental-treated animals was consistent with model animals.5. Observe indexes:Same as Chapter2.Chapter4:Research on Corrosion resistance and nickel permeability Of Nitinol brace1. Specimen collection and matching group:With inductively coupled plasma mass spectrum, test nickel content in blood specimens and local tissue specimens of two kinds of model animals before and3months after receiving experimental treatment. With scanning electron microscope, detect atomic ratio contents of nickel and titanium on the surface of Nitinol brace before and3months after receiving experiment treatment.2. Statistical treatment:Data were treated with statistical analysis software SPSS17.0using matching t test. The variances were represented by a mean±standard deviation. Compare nickel contents in blood specimens and local tissue specimens of two kinds of model animals before and3months after receiving experimental treatment. Compare ratios of atomic ratio content of titanium and nickel on the surface of Nitinol brace before and3months after experimental treatment. P<0.05indicated difference with a statistical significance.Results:Chapter1:1. The complex2of Nitinol and NormalGEN in scheme1was almost same as the complex of Nitinol and NormalGEN in scheme2and3, which was manufactured successfully according to predetermined scheme. Nitinol brace had four arms. The producted complexes of Nitinol and NormalGEN were sterilized so that it was safe to implant into body. The complexes could be prepared for experimental treatment of the model animals. 2. The instrument in scheme1was produced successfully. Metal material was medical stainless steel with laser welding technology. Material of the instrumental handle was engineering plastic material. It was obtuse angle formed by the handle and the front so that it was more advantageous to use the instrument which could be sterilized by high temperature-high pressure and low temperature plasma sterilization method. But, the instrument in scheme2and3failed to make.3. Use of the complex and instrument need drag with the help of the silk thread, relatively easily operated. Note:The type of complex and instrument were in practical application during subsequent experimental treatment of model animals accordingly.4. The scheme4was designed and determined by modifying the3scheme above. The trial operation convenience was superior to the former, and we could achieve effect of grasping, fixing, releasing and retrieving. But, the new complex has not been produced.Chapter2:1. As originally planned,2cases were simple modeling,5cases experimental treatmented. Model was reliable and operation smooth. The action of simple reconstruction was completed within1minute.2. The two simple modeling animals were stable during the process of operation and postoperative survived with incision healed well, no cerebrospinal fluid leakage, no nervous dysfunction. Five cases of experimental treatmented animals all survived. Postoperative situation was same as the two model animals.3. Head lateral and oblique X-rays films showed clear edge of middle skull base lateral bone defects about10mm in diameter of simple modeling animals without other abnormalities, and showed that Nitinol brace was clear without artifact or shift and four support arm without bending deformation in experimental treatment animals.64-slice spiral CT scanning followed by volume reconstruction and maximum intensity projection further confirmed these results.1.5TMRI scanning showed that brain contusion performance in the surgical field, while no brace images and interfering signals at corresponding to the location of experimental treatment animals.4. Local and mild inflammatory response with granulation tissue growing scar-like could be seen in the operative area of simple modeling animal by naked eye and on its tissue sections by HE staining under the light microscope. In addition, we could see that NormalGEN were not all absorbed in the operative area of experimental treatment animals, and that Nitinol brace was embedded steadily. A small amount of scar tissue attached to a small part of brace surface, but most of the other surface is smooth and complete.Chapter3:1. The first case of simple modeling animal died predictably from CSF rhinorrhea. which confirmed reliable model. The second predetermined simple modeling animal was diverted into experimental treatment after half an hour. Therefore,6cases received experimental treatment. The action of simple reconstruction was completed within1minute.2. All animals were stable during the process of operation. The first case of simple modeling animal appeared persistent postoperative cerebrospinal fluid rhinorrhea, unable to walk, transient conscious after resuscitation, drowsy after four hours, lethargy after one day, coma after three days and death after five days. Six cases of experimental treatment animals survived well. The postoperative course was same as described in Chapter2.3. head up-down positional X-ray film showed that Nitinol brace was clear without artifact or shift, four support arm without bending deformation and ideally position relative to the frontal sinus bone defect in experimental treatment animals.64-slice spiral CT scanning followed by volume reconstruction and maximum intensity projection further confirmed these results.1.5TMRI scanning showed that brain contusion performance in the surgical field, while no brace images and interfering signals at corresponding to the location of experimental treatment animals. Dead simple modeling animal had not been checked. 4. Autopsy of simple modeling animal confirmed the operative region and intracranial organizations widely severe inflammation. The thin layer of mucous membrane tissue grew on skull base defect surface of animals receiving experimental treatment with layered scar tissue forming below, and not fully absorbed meningeal built organizations staggered nitinol stents embedded in a solid. Slice results are basically same as Chapter2.Chapter4:1. Nickel contents in blood specimens and local tissue specimens of animals modeling with middle skull base defect and cerebrospinal fluid leakage before and3months after receiving experimental treatment was respectively0.4180±0.09706,9.6680±2.93828,0.4440±0.08173,9.0320±3.45773, had no significant difference (P values were respectively0.240and0.581, both greater than0.05). Nickel contents in blood specimens and local tissue specimens of animals modeling with frontal sinus defect and cerebrospinal fluid rhinorrhea before and3months after receiving experimental treatment was respectively0.4420±0.06979,11.0600±2.68480,0.4360±0.08204and10.7780±2.45873, had no significant difference (P values were respectively0.772and0.531, both greater than0.05).2. Ratios of atomic ratio content of titanium and nickel on the surface of Nitinol brace before and3months after experimental treatment of reconstructing middle skull base defect and cerebrospinal fluid leakage was respectively0.9847±0.00350and0.9832±0.00583without significant difference (P=0.617, greater than0.05). Ratios of atomic ratio content of titanium and nickel on the surface of Nitinol brace before and3months after experimental treatment of reconstructing frontal sinus defect and cerebrospinal fluid rhinorrhea was respectively0.9864±0.00365without significant difference (P=0.819, greater than0.05).Conclusion1. Complex of Nitinol brace and NormalGEN was successfully designed and manufactured, easy to use.2. Successfully established two kinds of animal models including middle skull base defect with cerebrospinal fluid leakage and frontal sinus defect and cerebrospinal fluid rhinorrhea, both stable and reliable; the former can happen self-healing, the latter has deadly cerebrospinal fluid leakage3. Complex of Nitinol brace and NormalGEN was successfully applied to reconstruct the two kinds of model animals, easy and safe to use. There was no evidence on nickel toxicity.
|
Related Dissertations
- Study of Control Algorithm of Shape Memory Alloy Based Free Inflatable Rectal Expansion Device,TH789
- Study on the Corrosion Behavior of Fe-based and Cu-based Shape Memory Alloy,TG139.6
- With shape memory alloy (SMA) fiber composite box driven nonlinear deformation of thin-walled beams,TB33
- Discussion on Development of SMA-Based Flexible Robot Finger,TP241
- Research on Squid Fin Like Propelle Based on SMA,U664.3
- The Control Technique Research of Rotary SMA Actuator,TP273.4
- Research on the Invasive-Surgery Active-Catheter Navigating Robot Drive and Control Techniques,TH772
- Basic Study on Valveless Micropump Driven by Shape Memory Alloy,TG139.6
- Shape Memory Alloy driven micropump,TG139.6
- Cu - Al - ( Ni ) - Mn Shape Memory Alloy Preparation and Related Properties of,TG139.6
- Study of SMA Micro-actuator and Bi-stable MEMS Relay,TM58
- Prediction of Shape Memory Alloy Recovery Stress Based on BP Neural Networks,TG139.6
- Studies on Constitutive Model for Shape Memory Alloy in Large Strain Deformation,TG139.6
- Cinical Observation of Shape Memory Alloy IUD,R169.4
- Research on Flexible Actuator Based on Shape Memory Alloy,TP215
- The Study of Backward Extrusion Process for Ti-Ni Alloy Tube,TG376
- Study on Micro-Displacement Actuator of Magectically Controlled Shape Memory Alloy,TG139.6
- Test System of Xternalproperties in Magnetically Controlled Shape Memory Alloy of Using Labview,TG139.6
- Self-sensing Properties of Magnetic Shape Memory Alloy Actuator,TG139.6
- Design Gecko Inspired Robot Driven by Shape Memory Alloy Actuator,TP242
- The Desige of Structure and Experiment of on Flexible Biomimetic Fish Fin Based on Shape Memory Alloy,TB17
CLC: > Medicine, health > Surgery > Of surgery > Head and Neurosurgery > Brain
© 2012 www.DissertationTopic.Net Mobile
|