Skeletal muscle is known to be set at an over-stretched length in clinical tendon transfer. Such chronic stretching of skeletal muscle increases the serial sarcomere number required for muscle adaptation. Passive tension of the muscle must be affected during the adaptation. Thus, the objective of this study was to clarify the origin of increased passive tension after stretched tendon transfer in an animal model. The distal tendon of the extensor digitorum of the second toe was transposed to the extensor retinaculum at 3.7 mm of muscle sarcomere length. The contralateral muscle served as control. Muscle passive length-tension curves were measured at 1 week and 4 weeks after the transfer to the bilateral muscles. After functional measurements were taken, the muscles were dissected into fiber bundles and single muscle fibers to measure their passive mechanical properties with a micro force transducer. Passive tension was increased in the transferred muscle with a steeper inclination and leftward shift of muscle length-tension curve. Elastic modulus of the transferred fiber bundle increased at both time points, while those of the transferred single fibers increased only at 1 week. Results of the study suggest that the transferred muscle increased passive tension mainly due to proliferation of extracellular connective tissue within the muscle. Increased passive tension was a characteristic feature for the transferred muscle, which may ultimately represent a target for therapeutic intervention to optimize muscle function.

Skeletal muscles are overstretched following limb lengthening procedures. Muscles can adapt to this lengthening by adding new sarcomeres in series. Recent developments in limb lengthening provide adult patients more opportunities to undergo limb lengthening procedures. The purpose of this study was to clarify the difference in muscle adaptation between adult and young groups using a rabbit model of limb lengthening. Five mature (10-43 month old) and 6 immature (3-4 month old) white rabbits underwent tibial osteotomy. After a 1-week lag phase, tibial lengthening was applied at a rate of 1.4 mm/day for 2 weeks. Animals were euthanized after the completion of lengthening. Both hindlimbs were immersed in buffered formalin with the ankle and knee at a right angle. Muscle belly length, muscle fiber bundle length and sarcomere length were measured, and sarcomere number and internal tendon length were calculated in five representative muscles around the lengthened segment. Muscle belly length increased in all the lengthened muscles compared with the corresponding contralateral muscles regardless the group. Aponeurosis length increased significantly in one muscle for the adult group and three muscles for the young group. Sarcomere length tended to be longer or was significantly longer in the lengthened muscles. Serial sarcomere number significantly increased in 3 lengthened muscles in the adult group with a more conspicuous increase in the amount, while this occurred in 2 muscles in the young group with only a tiny increase. The predominant processes of skeletal muscle adaptation to the limb lengthening are sarcomere number addition in muscle fibers for the adult group and elongation of internal tendon for the young group.

Although magnetic resonance imaging (MRI) is frequently used to assess the lumbar spine, there are few reports in the medical literature that have evaluated using MRI immediately following spinal surgery. Furthermore, descriptions of the subdural changes after lumbar spine surgery are also infrequent. In this paper, we present two cases with subdural change seen on MRI immediately after lumbar surgery. Both the patients had mild symptoms that resolved spontaneously, and the follow-up MRI scans showed resolution of the subdural changes. Subdural changes should be considered as one of the possible causes of unexpected symptoms in patients following lumbar spinal surgery.
Follow-Up Studies ; Humans ; Magnetic Resonance Imaging ; Spine ; Subdural Space

Here we present a case of hemorrhagic lumbar facet cyst presenting with progressive radiculopathy only on the contralateral side. If a patient has previous back pain or neuropathy for several months and then suddenly deteriorates, hemorrhagic facet cyst of the lumbar spine should be part of the differential diagnosis. However, as in the present case, we should be aware that there is a possibility of a contralateral lesion.
Back Pain ; Diagnosis, Differential ; Hematoma ; Humans ; Leg ; Radiculopathy ; Spine ; Zygapophyseal Joint

Acute calcific tendinitis of the longuscolli is a self-limiting inflammatory condition caused by calcium hydroxyapatite deposition in the longuscolli tendon. Although several case reports have described its radiological presentation, few reports provide detailed chronological accounts through symptomatic and radiologic resolution. A 59-year-old woman presented with severe neck pain and stiffness of a few days duration as well as moderate discomfort when swallowing. Lateral radiographs revealed a large calcium deposit anterior to the C1.C2 joint and swelling of the prevertebral soft tissue from C1 to C5. CT and magnetic resonance imaging showed fluid in the retropharyngeal gap.A soft collar and non-steroidal anti-inflammatory drug were prescribed, without antibiotics. At 4 months after presentation, the calcium deposit and all symptoms had resolved completely. Although this disease is comparatively rare, physicians should keep it in mind when a patient presents with acute severe neck pain.
Anti-Bacterial Agents ; Calcium ; Deglutition ; Durapatite ; Female ; Humans ; Joints ; Magnetic Resonance Imaging ; Middle Aged ; Neck Pain ; Tendinopathy* ; Tendons