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A short thumb with radial angulation causes loss of hand function in patients with Apert syndrome. Although past reports have described various procedures for the correction of the thumb, there has been no consensus on the best procedure. This study aimed to assess the clinical and radiographic results of a surgical technique for the correction of a thumb radial angulation deformity: open-wedge osteotomy using a bone-graft substitute. Ten patients (18 thumbs) who underwent open-wedge osteotomy on the proximal phalange using a bone-graft substitute were evaluated retrospectively. The open-wedge osteotomies had been performed at the center of the proximal phalanx. Thumb radial angles and thumb lengths were measured on radiographs, and the clinical results were investigated, including bone union and complications. The median patient age at the time of surgery was 5.8 years, and the average follow-up period was 6.7 years. The average thumb radial angle was 57.3° preoperatively, 6.5° immediately postoperatively, and 19.8° at the most recent follow-up. The average thumb length was 12.1 mm preoperatively, 18.1 mm immediately postoperatively, and 22.3 mm at the most recent follow-up, indicating an extension effect of more than 50% immediately postoperatively. In all cases, the artificial bone had been absorbed and developed into autologous bone, and there were no complications such as infection and skin necrosis. These findings suggest that open-wedge osteotomy with an artificial bone substitute is simple and effective for treating radial-angulation deformities in patients with Apert syndrome. Level of evidence: Level IV - retrospective case series.

Patients with pediatric trigger thumb present with fixed contracture of the interphalangeal joint (IPJ) or snapping of the thumb. We applied a hand-based dynamic splint using coils at the IPJ. The aim of this study was to report the clinical outcomes of splint therapy versus observation. One hundred twenty-nine thumbs (112 patients and 57 boys) were examined retrospectively. At initial presentation, parents selected the treatment after explanation of pathology and consents were obtained. Treatment was concluded when full extension or resolution of the involved IPJ was achieved; alternatively, surgical treatment was offered for patients who failed to improve. Improvement in extension loss to 0° and hyperextension was defined as resolution of the IPJ. Surgery was not selected as a first-line treatment strategy in any of the cases in this study. The rate of resolution was 59% at 31 months of follow-up in the splint group (99 thumbs) and 43% at 30 months in observation group (30 thumbs); there was no significant difference between the groups (P = 0.15). Twenty-one thumbs showed locking of the IPJ in the extended position during splint therapy, but all recovered with a 71% rate of resolution. The splint group showed a higher rate of resolution than the observation group; however, there was no significant difference between therapies. Our study showed that 55% of patients with pediatric trigger thumb showed resolution following conservative treatment for an average of 30 months until surgery could be performed under local anesthesia. Splint therapy and observation are viable treatment options prior to surgery.

When animals repeatedly receive a combination of neutral conditional stimulus (CS) and aversive unconditional stimulus (US), they learn the relationship between CS and US, and show conditioned fear responses after CS. They show passive responses such as freezing or panic movements (classical or Pavlovian fear conditioning), or active behavioral responses to avoid aversive stimuli (active avoidance). Previous studies suggested the roles of the cerebellum in classical fear conditioning but it remains elusive whether the cerebellum is involved in active avoidance conditioning. In this study, we analyzed the roles of cerebellar neural circuits during active avoidance in adult zebrafish,. When pairs of CS (light) and US (electric shock) were administered to wild-type zebrafish, about half of them displayed active avoidance. The expression of botulinum toxin, which inhibits the release of neurotransmitters, in cerebellar granule cells or Purkinje cells did not affect conditioning-independent swimming behaviors, but did inhibit active avoidance conditioning. Nitroreductase-mediated ablation of Purkinje cells in adult zebrafish also impaired active avoidance. Furthermore, the inhibited transmission of granule cells or Purkinje cells resulted in reduced fear-conditioned Pavlovian fear responses. Our findings suggest that the zebrafish cerebellum plays an active role in active avoidance conditioning. Significance Statement An animal can associate a neutral conditioned stimulus and an aversive unconditioned stimulus, and escape to avoid an aversive stimulus. This is called active avoidance conditioning and is essential for an animal’s survival. Although the amygdala and habenula nucleus are reportedly involved in active avoidance conditioning, the roles of other brain regions are largely unknown. We describe the roles of the cerebellum during active avoidance in adult zebrafish. The neurotoxin botulinum toxin-mediated inhibition of granule cells or Purkinje cells, or the ablation of Purkinje cells, suppressed active avoidance conditioning. Our findings indicate that the cerebellum plays a positive role in active avoidance conditioning.

We report a post-traumatic lumbar facet cyst in which results of magnetic resonance imaging (MRI) performed at the time of injury were available. The patient was a 59-year-old man who presented with severe low back and right leg pain immediately after injury of his sacroiliac region in a traffic accident. MRI at the time of injury revealed high intensity signal change in the right facet joint at L4/5. Re-examination 5 months after the injury with MRI revealed a cyst, which was continuous with the facet joint. Surgical resection of the cyst yielded satisfactory results. We describe detailed MRI findings for this case and review the literature on traumatic juxta-facet cyst in the lumbar spine.