Flexibility and fatigue evaluation of oblique as compared with anterior lumbar interbody cages with integrated endplate fixation.

OBJECTIVE: This study was undertaken to quantify the in vitro range of motion (ROM) of oblique as compared with anterior lumbar interbody devices, pullout resistance, and subsidence in fatigue. METHODS: Anterior and oblique cages with integrated plate fixation (IPF) were tested using lumbar motion segments. Flexibility tests were conducted on the intact segments, cage, cage + IPF, and cage + IPF + pedicle screws (6 anterior, 7 oblique). Pullout tests were then performed on the cage + IPF. Fatigue testing was conducted on the cage + IPF specimens for 30,000 cycles. RESULTS: No ROM differences were observed in any test group between anterior and oblique cage constructs. The greatest reduction in ROM was with supplemental pedicle screw fixation. Peak pullout forces were 637 ± 192 N and 651 ± 127 N for the anterior and oblique implants, respectively. The median cage subsidence was 0.8 mm and 1.4 mm for the anterior and oblique cages, respectively. CONCLUSIONS: Anterior and oblique cages similarly reduced ROM in flexibility testing, and the integrated fixation prevented device displacement. Subsidence was minimal during fatigue testing, most of which occurred in the first 2500 cycles.

Canine distemper in endangered Ethiopian wolves.

The Ethiopian wolf (Canis simensis) is the world's rarest canid; ≈500 wolves remain. The largest population is found within the Bale Mountains National Park (BMNP) in southeastern Ethiopia, where conservation efforts have demonstrated the negative effect of rabies virus on wolf populations. We describe previously unreported infections with canine distemper virus (CDV) among these wolves during 2005-2006 and 2010. Death rates ranged from 43% to 68% in affected subpopulations and were higher for subadult than adult wolves (83%-87% vs. 34%-39%). The 2010 CDV outbreak started 20 months after a rabies outbreak, before the population had fully recovered, and led to the eradication of several focal packs in BMNP's Web Valley. The combined effect of rabies and CDV increases the chance of pack extinction, exacerbating the typically slow recovery of wolf populations, and represents a key extinction threat to populations of this highly endangered carnivore.

Outcome of anterior cervical discectomy and fusion as perceived by patients treated for dominant axial-mechanical cervical spine pain.

STUDY DESIGN: An extensive outcome questionnaire using a visual analog scale, the North American Spine Society Satisfaction Questionnaire, a Modified Roland and Morris disability index, and a modified Oswestry Disability Index was used to assess the outcome of anterior cervical discectomy and fusion for those with neck pain. OBJECTIVE: To document the clinical outcome for 87 patients who underwent anterior cervical discectomy and fusion for the primary indication of neck pain, as assessed after an average follow-up period of 4.4 years. SUMMARY OF BACKGROUND DATA: Clinical outcome studies of anterior cervical discectomy and fusion with validated patient-perceived outcome measurements are few. METHODS: From the authors' database, 87 patients were identified who had undergone an anterior cervical discectomy and fusion for primary indication of dominant neck pain, and who had completed an extensive outcome questionnaire regarding pain and self-function at a mean 4.4-year follow-up assessment. RESULTS: This study documents a self-perceived satisfactory outcome rate of 82%. Patients reported on improvement of pain using visual analog scales, on function using modified Oswestry and modified Roland-Morris disability indexes, and on satisfaction using the North American Spine Society outcome tool. On an assessment 4.4 years on the average after the surgery, 82% of the patients (71/87) self-perceived their outcome to be good, very good, or excellent. Pain improvement was reported by 93% of the patients (81/87), whose average visual analog rating changed from 8.4 before surgery to 3.8 after surgery. The self-rated functional status improved approximately 50% on both the Oswestry and the modified Roland-Morris disability indexes. CONCLUSIONS: Properly selected patients who present with a primary indication of chronic neck pain report a high percentage of change in their self-perceived level of pain and function when treated with anterior cervical discectomy and fusion. Patients' self-expressed improvement with surgical management, as compared with their preoperative dissatisfaction because of their neck condition, documents that this surgical treatment is a reasonable option.