The prevalence of indications and contraindications to cervical total disc replacement.

BACKGROUND CONTEXT: Although the prevalence of indications and contraindications to lumbar total disc replacement (TDR) has been evaluated, no study to date has quantified the potential candidacy for cervical disc replacement in practice. PURPOSE: To report the potential candidacy rate for cervical TDR from both an academic and private practice spine surgery setting. STUDY DESIGN/SETTING: Retrospective case series. PATIENT SAMPLE: Patient record review of 167 consecutive patients who underwent cervical spine surgery by 1 of 2 orthopedic spine surgeons between January 1, 2003 and January 1, 2005. OUTCOME MEASURES: Evaluation of potential candidacy for cervical TDR, with emphasis on both contraindications and indications. METHODS: In this study, we used the published contraindications and indications listed in trials of four different cervical disc arthroplasty devices: ProDisc-C (Synthes Spine, West Chester, PA), PRESTIGE LP (Medtronik Sofamor Danek, Memphis, TN), Bryan Cervical Disc prosthesis (Medtronik Sofamor Danek, Memphis, TN), and Porous Coated Motion (PCM; Cervitech, Rockaway, NJ). The proportion of patients who met both inclusion and exclusion criteria was calculated. We also examined the proportion of patients who would be candidates for cervical TDR if the indications were expanded to include the treatment for adjacent segment disease (ASD). RESULTS: Of the 167 patients (mean age 50.8 years, range 20-89 years) reviewed, 91.6% (153/167) had fusion surgery and 8.4% (14/167) had nonfusion surgery. Fifty-seven percent (95/167) had absolute contraindications to cervical TDR, and within this group the average number of contraindications was 2.1 (SD=1.2, range 0-5). Forty-three percent (72/167) met the strict inclusion criteria, and had no exclusion criteria. If the indications were expanded to include treatment for ASD, an additional 4.2% (7/167) of the patients would have qualified as candidates for cervical TDR. CONCLUSIONS: Compared with lumbar TDR, total disc replacement may have a larger potential role in the treatment of cervical degenerative conditions, as 43% of patients would have met the strict criteria for TDR candidacy, or 47% if the indications were expanded to include treatment for ASD.     

Mediastinal tumors: biopsy under US guidance

Percutaneous biopsies of mediastinal tumors were successfully performed under sonographic guidance in 14 of 21 patients. In 10 of 11 malignant lesions, malignancy was determined by means of cytologic and histologic examination of the specimens obtained. A histologic diagnosis was reached in seven patients with malignant mediastinal tumors, including all four cases of Hodgkin lymphoma. Mediastinal biopsy under sonographic guidance is a technically simple, rapid, and accurate procedure, but its application is limited to tumors of the anterior mediastinum.     

A new optical treatment for oscillopsia.

A simple optical device (spectacles plus contact lens) enabling viewing of the real world with either partial or almost-complete retinal image stabilisation has been tested in patients with oscillopsia caused by nystagmus. The device gave a useful improvement in vision in two of 14 patients. Reasons for success and failure were clear and are discussed. Obvious contraindications include severe optic atrophy, titubation and dementia. Net benefit is also unlikely if there is a good null point or area to the nystagmus, or if acuity (corrected but unstabilized) is 6/9 or better. It is not suitable for the treatment of oscillopsia caused by failure of the vestibulo-ocular reflex.     

The diagnostic usefulness of isocitrate dehydrogenase (ICDH) in the marmoset (Callithrix jacchus)

Marmosets were given either a hepatotoxin, carbon tetrachloride, orally or an i.m. injection of a mytoxin, chlorpromazine. Although muscle damage alone caused small increases in the plasma levels of lactate dehydrogenase, alanine aminotransferase, aspartate aminotransferase and isocitrate dehydrogenase (ICDH), only the isoenzyme analysis of ICDH can differentiate definitely between liver and muscle damage. Only very severe muscle damage can increase the plasma concentration of this enzyme but, in this case, the elevation of plasma creatinine kinase levels helps differentiation. It is recommended that the elevation of ICDH is the most specific indicator of hepatic damage in the marmoset.     

Occult cerebral vascular malformations: high-field MR imaging

Occult cerebral vascular malformations (OCVMs) have characteristic appearances on high-field magnetic resonance (MR) images. These consist of circumscribed regions of low intensity, most prominent on T2-weighted images and representing hemosiderin deposits. Interspersed within most of these lesions are multiple areas of various signal intensity patterns, which correspond to hematomas in different stages of evolution and to fibrous regions containing calcium as well as hemosiderin. Forty-six lesions were found in 19 patients (34 supratentorial and 12 infratentorial). The supratentorial lesions tended to be subcortical or periventricular. Computed tomography depicted 24 of the 46 lesions demonstrated by high-field MR. Comparison of images obtained with both low-field MR (0.12 T and 0.35 T) and high-field MR (1.5 T) revealed that high-field MR imaging was superior in depicting OCVMs. High-field MR appears to be both sensitive and specific for OCVMs and may obviate the need for possible biopsy of these lesions.