In the recent years, there has been a growing interest in research community towards the application of smart materials for bio-medical structural health monitoring. Amongst the smart materials, directly bonded piezo sensors (DBPS), based on the electro-mechanical impedance (EMI) technique, have been successfully employed for the above purpose. The principle behind the EMI technique is that high frequency excitations (typically > 30 kHz) generated by a surface bonded PZT patch are used to detect changes in structural drive point impedance caused by cracks or any other type of damage. Bone healing and damage have been shown to be successfully monitored using the DBPS. However, in most of the diagnostic cases of live human and animal subjects, directly bonding a PZT patch is always an irritant or hazard for a live subject. To circumvent direct bonding, the authors have developed and experimentally demonstrated a non-bonded piezo sensor (NBPS) configuration as a good alternative to DBPS while maintaining the effectiveness of measurement well within discernible limits. This paper presents further improvement in the NBPS configuration aiming at autonomous operation of the gripping mechanism using shape memory alloy (SMA) wires. The experiments are performed on replicas of femur bone in healthy and osteoporosis state. This paper shows the effective use of SMA clamping for bone identification and its damage assessment in comparison to earlier mechanical gripping using jubilee clamps. This paper also covers impedance based identification applied to SMA and clamp based NBPS configurations. In place of raw admittance signatures, effective drive point impedance is utilized for the purpose of bone diagnostics which provides a more realistic assessment of the condition of bone.
Alloys ; Animals ; Constriction ; Diagnosis ; Electric Impedance ; Femur ; Hand Strength ; Humans ; Memory ; Osteoporosis

PURPOSE: Penetrating vascular trauma though less common poses a challenge to all Surgeons. This study was designed to analyse the profile, management modalities of vascular trauma and the outcomes thereof at a Trauma Care Centre in a Tertiary care setting in hostile environment in India. METHODS: A prospective review of all patients with arterial and venous injuries being transferred to the Trauma Center at out Tertiary Care Center between June 2015 and May 2018 was done. Demographics, admission data, treatment, and complications were reviewed. RESULTS: There were a total of 46 patients with 65 vascular injuries, 39 arterial injuries and 26 venous injuries. The age range was 21 to 47 years. Nineteen patients had both arterial and venous injuries. A total of 42 cases presented within 12 hours of injury and complete arterial transections were found in 33 cases (80.49%). There were three mortalities (6.52%) and three amputations (8.33%). The overall limb salvage rate was 91.67% with popliteal artery being the commonest injured artery. Poor prognosticators for limb salvage were increasing time to present to the trauma centre, hypovolemic shock, multi-organ trauma and associated venous injuries. CONCLUSIONS Penetrating missile trauma leading to vascular injuries has not been widely reported. Attempting limb salvage even in cases with delayed presentation should be weighed with the threat to life before revascularisation and should preferably be done at a centre with vascular expertise. A team approach with vascular, orthopaedic, general surgeons, and critical care anaesthesiologists all aboard improve the outcomes manifold. Use of tourniquets and early fasciotomies have been emphasized as is the use of native veins as the bypass conduit. This is probably the largest study on penetrating Vascular trauma in anti-terrorism ops from the Indian subcontinent. It highlights the significance of prompt recognition and availability of vascular expertise in optimally managing cases of vascular trauma.