Patients with spine fractures and ASD are at high risk for complications and death and should be counseled accordingly. Multilevel posterior segmental instrumentation allows effective fracture healing. AS and DISH patients represent similar patient populations for the purpose of treatment and future research.

Screws placed into cancellous bone in orthopedic surgical applications, such as fixation of fractures of the femoral neck or the lumbar spine, can be subjected to high loads. Screw pullout is a possibility, especially if low density osteoporotic bone is encountered. The overall goal of this study was to determine how screw thread geometry, tapping, and cannulation affect the holding power of screws in cancellous bone and determine whether current designs achieve maximum purchase strength. Twelve types of commercially available cannulated and noncannulated cancellous bone screws were tested for pullout strength in rigid unicellular polyurethane foams of apparent densities and shear strengths within the range reported for human cancellous bone. The experimentally derived pullout strength was compared to a predicted shear failure force of the internal threads formed in the polyurethane foam. Screws embedded in porous materials pullout by shearing the internal threads in the porous material. Experimental pullout force was highly correlated to the predicted shear failure force (slope = 1.05, R2 = 0.947) demonstrating that it is controlled by the major diameter of the screw, the length of engagement of the thread, the shear strength of the material into which the screw is embedded, and a thread shape factor (TSF) which accounts for screw thread depth and pitch. The average TSF for cannulated screws was 17 percent lower than that of noncannulated cancellous screws, and the pullout force was correspondingly less. Increasing the TSF, a result of decreasing thread pitch or increasing thread depth, increases screw purchase strength in porous materials. Tapping was found to reduce pullout force by an average of 8 percent compared with nontapped holes (p = 0.0001). Tapping in porous materials decreases screw pullout strength because the removal of material by the tap enlarges hole volume by an average of 27 percent, in effect decreasing the depth and shear area of the internal threads in the porous material.

Recommendation 1: When selecting the appropriate outcome measures for clinical or research purposes, consider domains that best measure what are most important to patients. Measures that are valid, reliable, and responsive to change should be considered first. Other considerations include the number of items required (especially in the context of multiple measures), whether the measure is validated in the relevant language, and the associated costs or fees. Strength: Strong Recommendation 2: Domains of greatest importance include pain, function, and quality of life. If cost utilization is a priority, then preference-based measures should be considered. For pain, we recommend the VAS and NRPS because of their ease of administration and responsiveness. For function, we recommend the ODI and RMDQ. The SF-36 and its shorter versions are most commonly used and should be considered if quality of life is important. If cost utility is important, consider the EQ-5D or SF-6D. Psychosocial tests are best used as screening tools prior to surgery because of their lack of responsiveness. Complications should always be assessed as a standard of clinical practice. Return to work and medication use are complicated outcome measures and not recommended unless the specific study question is focused on these domains. Consider staff and patient burden when prioritizing one's battery of measures.

Surgical decompression for the treatment of cervical spondylotic myelopathy was associated with improvement in functional, disability-related, and quality-of-life outcomes at one year of follow-up for all disease severity categories. Furthermore, complication rates observed in the study were commensurate with those in previously reported cervical spondylotic myelopathy series.