Minimally invasive techniques

Oyekan AO, Botting JH (1986) A minimally invasive technique for the study of intravascular platelet aggregation in anesthetized rats. J Pharmacol Meth 15 271-277 Smith D, Sanjar S, Herd C, Morley J (1989) In vivo method for the assessment of platelet accumulation. J Pharmacol Meth 21 45-59... 

Against this backdrop, research into less invasive approaches to treat valvular disease has been intensified. In the surgical realm, minimally invasive techniques, with its attendant patient and procedural related limitations, have been tried with some success but traditional valvular operations still remain the norm. At the same time, great strides have been made in percutaneous approaches to treatment of valvular disease. Two valvular disease states in which percutaneous balloon valvuloplasty have had great success are in the treatment of pulmonic stenosis and mitral stenosis. 

Lymphoscintigraphy and sentinel node biopsy is a minimally invasive technique that samples first echelon lymph nodes and predicts the need of more extensive neck dissection. The accuracy has been assessed on oral cancers undergoing preoperative PET/CT followed by sentinel node biopsy (Civantos et al. 2003). Gross tumour replacement of lymph nodes and redirection of lymphatic flow represented a significant technical issue in oral carcinomas (Civantos et al. 2006). 

Percutaneous cementoplasty (PC) consists of injecting acrylic cement (polymethylmethacrylate) in bone and is a perfect example of a minimally invasive technique in the musculoskeletal system. PC has been performed since 1984. Its role is to consolidate weight-bearing bone and to treat pain. Bone packing with acrylic cement is a procedure aimed at preventing pathological fractures and pain in patients with vertebral body lesions and acetabular metastasis. 

Saliba, L, Woods, O., 2011. Hyaluronic acid fat graft myringoplasty a minimally invasive technique. Laryngoscope 121, 375—380. 

Currently, these minimally invasive techniques are limited by the size and location of the liver tumors. The maximum size of the ablation lesion is up to 5 cm for most techniques. With the use of liquid-cooled applicator systems and improved application techniques coagulation necrosis of up to 6-8 cm can be created (Vogl et al. 2003). For reduction of tumor relapse a safety margin of 1 cm to the tumor border is necessary. On this account the maximum tumor size is between 4 and 6 cm in diameter for the lesions treatable with LITT. 

The results presented here must still be compared with a variety of other minimally invasive techniques. Transarterial chemoembolization is a procedure involving the injection of lipiodol and a chemotherapeutic agent into the hepatic artery. The intention is to produce selective ischemic injury to the tumor, which relies mainly on the arterial circulation. Ka nematsu et al. (1993) did the first comparative study between hepatic resection in 67 patients and transcatheter arterial embolization (TAB) in 20 patients with resectable disease. The 1-year, 3-year, and 5-year cumulative survival rates for 67 patients undergoing surgery were 89.1%, 74.6%, and 54.6% respectively and for the 20 patients treated with TAB, 90%, 50%, and 17.50% respectively. Surgery therefore provided more favorable results (Kanematsu et al. 1993). 

Palliative treatment options for recurrent head and neck cancer are limited by the proximity of vital vascular and neural structures and the aggressive nature of most of these tumors. Laser-induced interstitial thermotherapy (LITT) is a recently developed minimally invasive treatment modality. It is a minimally invasive technique for local tumor destruction within solid organs. 

Regarding the overall good prognosis of WT, followup imaging should be made with minimally invasive techniques. However, since relapsed patient may be... 

Many different non- or minimally-invasive techniques have been investigated for measuring the response of tissues to PDT treatment in vivo, either qualitatively or quantitatively, as summarized in Table 2. To date these techniques have mainly been applied in preclinical animal model studies, but there are a number of examples in the literature where some of the methods have been used in patients. Two of the optical imaging techniques, namely Doppler optical coherence tomography (DOCT) and bioluminescence imaging (BLI) will be illustrated here. 

The liquid/powder ratio (L/P) is an important aspect of the cement that affects the workability and the injectability of the paste. Generally, low L/P ratio s cause flowable and viscous pastes, while liquid deprivation reduces the injectability of the paste. On the other hand, excess aqueous solution is often associated with the phenomenon of filter-pressing, which implies that the liquid flows faster than the ceramic particles (Bohner et al. 2010). Although liquid films surrounding the particles keep the particles separated, improve the fluidity and allow injection by minimally invasive techniques, the final setting time of the cement increases due to delayed crystallization, which causes a weaker structure due to a high micro and nanoporosity in the final cement (Ginebra et al. 2004 Espanol et al. 2009). 

Vertebroplasty and kyphoplasty are minimally invasive techniques whose aim is to stabilize vertebral compression fractures and provide immediate pain relief with minimal risk. These procedures consist in the percutaneous injection of the PMMA cement into the vertebral body, thus avoiding the morbidity and mortality associated with open surgery [24]. Radiograph images of percutaneous vertebroplasty are shown in Figure 12.2 [25]. 

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