Anatomical study of the medial plantar proper digital nerve using ultrasound.

PURPOSE: To determine whether ultrasound allows precise assessment of the course and relations of the medial plantar proper digital nerve (MPPDN). MATERIALS AND METHODS: This work was initially undertaken in six cadaveric specimens and followed by a high-resolution ultrasound study in 17 healthy adult volunteers (34 nerves) by two musculoskeletal radiologists in consensus. Location and course of the MPPDN and its relationship to adjacent anatomical structures were analysed. RESULTS: The MPPDN was consistently identified by ultrasound along its entire course. Mean cross-sectional area of the nerve was 0.8 mm2 (range 0.4-1.4). The MPPDN after it branches from the medial plantar nerve was located a mean of 22 mm (range 19-27) lateral to the medial border of the medial cuneiform. More distally, at the level of the first metatarsophalangeal joint, mean direct distances between the nerve and the first metatarsal head and the medial hallux sesamoid were respectively 3 mm (range 1-8) and 4 mm (range 2-9). CONCLUSION: The MPPDN can be depicted by ultrasonography. Useful bony landmarks for its detection could be defined. Precise mapping of its anatomical course may have important clinical applications. KEY POINTS: • The medial plantar proper digital nerve (MPPDN) rises from the medial plantar nerve to the medial side of the hallux. • Because of its particularly long course and superficial position, the MPPDN may be subject to trauma, resulting in a condition known as Joplin's neuroma. • The MPPDN can be clearly depicted by ultrasound along its entire course. Precise mapping of its anatomical course may have important clinical applications.

Percutaneous cryoablation for the treatment of osteoid osteoma in the adult population.

PURPOSE: To evaluate the technical feasibility and efficacy of percutaneous cryoablation for the treatment of osteoid osteoma (OO) in adults. METHODS AND MATERIALS: 21 patients (12 male and nine female; mean age, 29.9 years) who underwent CT-guided percutaneous cryoablation for the treatment of OO were retrospectively evaluated. Procedures were carried out under local anaesthesia and conscious sedation in 13 patients, and under general anaesthesia in eight patients. Then, the ablation zone was evaluated with post-procedure magnetic resonance imaging at 6 weeks. Clinical outcome was assessed using a visual analogue scale (VAS) to evaluate severity of pain before procedure, as well as at primary (6 weeks) and secondary follow-up (6-40 months). RESULTS: All procedures were technically successful. Median VAS scores were: 8 (range, 5-10) before procedure and after procedure, respectively, 0 (range, 0-2; p < .0001) and 0 (range, 0-7; p < .0001) at primary and secondary follow-up. There were three minor complications (14.3%) and no major complication. A single patient reported symptom recurrence (4.8%) at secondary follow-up and successfully underwent a second cryoablation procedure. CONCLUSION: CT-guided percutaneous cryoablation is safe and effective in the treatment of OO in adults, and can be accomplished without general anaesthesia in selected cases. KEY POINTS: • CT-guided percutaneous cryoablation of osteoid osteoma is safe and effective • Cryoablation allows precise visual control of the aggregated iceball during procedure • Percutaneous cryoablation can be accomplished without general anaesthesia in selected cases • Another advantage of cryoablation is reduction of immediate postprocedural pain • Post-procedure MRI is helpful in the evaluation of technical success.