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There is currently no structured classification system to quantitate heterotopic bone formation after artificial disk replacement procedures. The purpose of this work was to develop a method of classifying heterotopic bone formation that is reliable between investigators with different levels of training and easy to remember with only five gradations of severity. One hundred one radiographs of clinical patients and 17 microradiographs from nonhuman primates having undergone various types of disk replacement were classified by seven independent reviewers. The kappa statistics were calculated for interobserver variation between the seven participants with various levels of spinal training and the intraobserver error based on two assessments made at least 2 months apart. The interobserver reliability correlation coefficient for seven raters calculated using the intraclass kappa correlation coefficient and the Kish rho was r = 0.9683 (P < 0.0001). The intraobserver reliability based on readings at two time intervals at a minimum of 2 months apart was r = 0.8949 (P = 0.01). This classification of heterotopic ossification, periannular calcification, and ectopic bone formation associated with total disk arthroplasty proved to be highly reliable and reproducible.

SUMMARY: MR imaging of peripheral nerves has been described in relation to abnormalities such as nerve injury, entrapment, and neoplasm. Neuroma formation is a known response to peripheral nerve injury, and here we correlate the MRN appearance of postinjury neuroma formation with intraoperative findings. We also present the MR imaging features of surgical treatment with a synthetic nerve tube and nerve wrap on postoperative follow-up imaging.ABBREVIATIONS: MRN ϭ MR neurography; NIC ϭ neuroma in continuity; SPACE ϭ sampling perfection with application optimized contrasts by using different flip angle evolutions; SPAIR ϭ spectral adiabatic inversion recovery; STIR ϭ short tau inversion recovery P eripheral nerve injuries and entrapments may lead to formation of NIC, neuroma in completely severed nerves, and amputation neuroma. These lesions also demonstrate unique MRN appearances. This article presents MRN and surgical correlations of various posttraumatic neuromas with relevant case examples.

Many surgeons operating on patients with tarsal tunnel syndrome do not decompress the respective medial plantar and lateral plantar nerves and excise the septum. The authors' study validates the hypotheses that patients who are clinically suspected of having chronic compression of the tibial nerve and its branches at the ankle have higher tunnel pressures and that releasing these structures decreases the pressures.