Biomechanical Comparison of Spinal Fusion Methods Using Interspinous Process Compressor and Pedicle Screw Fixation System Based on Finite Element Method

OBJECTIVE: To investigate the biomechanical effects of a newly proposed Interspinous Process Compressor (IPC) and compare with pedicle screw fixation at surgical and adjacent levels of lumbar spine. METHODS: A three dimensional finite element model of intact lumbar spine was constructed and two spinal fusion models using pedicle screw fixation system and a new type of interspinous devices, IPC, were developed. The biomechanical effects such as range of motion (ROM) and facet contact force were analyzed at surgical level (L3/4) and adjacent levels (L2/3, L4/5). In addition, the stress in adjacent intervertebral discs (D2, D4) was investigated. RESULTS: The entire results show biomechanical parameters such as ROM, facet contact force, and stress in adjacent intervertebral discs were similar between PLIF and IPC models in all motions based on the assumption that the implants were perfectly fused with the spine. CONCLUSION: The newly proposed fusion device, IPC, had similar fusion effect at surgical level, and biomechanical effects at adjacent levels were also similar with those of pedicle screw fixation system. However, for clinical applications, real fusion effect between spinous process and hooks, duration of fusion, and influence on spinous process need to be investigated through clinical study.

Rehabilitation of Amputee with Recurrent Squamous Cell Carcinoma Arising from Postburn Scar: A Case Report

A 73-year-old woman who has been suffering from ulcer pain on left lower leg of burn scars visited our clinic for prosthesis rehabilitation. Symptom has been developed since 12 months ago. She burned herself with oil at the age of 40. Biopsy on the skin lesion revealed squamous cell carcinoma. Marjolin's ulcer is a rare but highly aggressive squamous cell cancer that is most often associated with chronic burn wounds. Patient had undergone multiple prior split-thickness skin grafts for recurrent squamous cell carcinoma. She had undergone a trans-tibial amputation and subsequently given adjuvant chemotherapy for recurrent disease. After amputee training the patient was able to walk by herself and could perform all activities of daily living independently. Cancer induced amputees need prostheses with intensive rehabilitation training program for ambulation to prevent deterioration of physical function and mental health due to immobilization. However, she developed another recurrence and decided not to undergo further surgery and eventually died in hospice care due to progressive metastatic disease.