Anterior spinal instrumentation combining a prosthetic disc nucleus with a flexible stabilization device: Manufacture and use in intervertebral disc repair

Artificial disc replacement alone is unable to completely cure cervical degenerative diseases; thus, a stabilization device markedly improves patient recovery. In order to meet this requirement, an anterior spinal instrumentation combining a prosthetic disc nucleus with a flexible stabilization device (ASI combining PDN/FD) was developed. An artificial disc was designed and manufactured using polyvinyl alcohol hydrogel (PVA-H) with a repeated freeze-melting technique, and subsequently the dehydration and swelling properties of the PVA-H were investigated. A canine animal model was then used to compare the differences in the degeneration of cervical discs adjacent to the operative segment with PDN/FD against a plate fixation system, without the interferences of brace intensity, which was ensured by pressure monitoring the dog's intervertebral disc adjacent to operative segments. The in vivo results demonstrated a clear decrease in the degeneration of the adjacent disc with the use of PDN/FD as compared with the plate fixation system. In conclusion, PDN/FD may offer a promising method for the treatment of cervical degenerative disease.

Entero-paraspinous fistula from recurrent spinal metastatic renal cell carcinoma

The authors report a case of entero-paraspinous fistula 2 years after T-12 corpectomy and instrumentation for spinal metastasis from renal cell carcinoma. The pathogenesis in the present case seems to have arisen from local recurrence of T-12 metastatic carcinoma in spite of radiation and corpectomy. As a result of previous nephrectomy and anterolateral dissection for the T-12 corpectomy, the jejunum adhered to the surgical site. Recurrent tumor at T-12 invaded the adherent small bowel loop, resulting in a fistulous communication between the small bowel lumen and the spinal wound. Loss of retroperitoneal fat, scarring, and adhesions from previous surgeries contributed to this complication by having the jejunum close to the T-12 corpectomy site, and eventually to its invasion by recurrent tumor. Avoidance of such a complication is difficult; however, total excision of the spinal malignancy, and when possible, creating a barrier cuff of fascia or fat around the spine to protect abdominal contents, are potential solutions.