Summary: This paper aimed to better describe the anatomy of the superficial anterior atlanto-occipital ligament of the craniocervical junction and discuss this ligament’s potential function and clinical implications. A broad literature review on the anatomical features and findings of the superficial anterior atlanto-occipital ligament was performed. The superficial anterior atlanto-occipital ligament is located anterior to the anterior atlanto-occipital membrane. However, the physiological role of the superficial anterior atlanto-occipital ligament is still unclear due to a lack of anatomical and biomechanical studies although one study has suggested that this ligament is a secondary stabilizer of the craniocervical junction. Further studies are needed to clarify the function and anatomy of the superficial anterior atlanto-occipital ligament.

Summary: An ossified left petroclinoid ligament was found during routine dissection of the skull base in an adult male cadaver. The petroclinoid ligament is clinically and surgically important given its anatomical relationships to cranial nerves III, V, and VI, so its ossification is a risk factor for injuries due to trauma, increased intracranial pressure, and vascular and tumor compression resulting in abducens and oculomotor palsies. The causes of petroclinoid ligament ossification are yet to be completely elucidated although several reports have associated them with age-related and physiological processes. Assessing the integrity of the petroclinoid ligament is important during skull base surgical interventions to avoid postoperative complications. Therefore, this paper reviews the petroclinoid ligament and its variation, the ossified petroclinoid ligament.

Summary: Background: Heart failure in severe aortic stenosis (AS) before aortic valve has a poor prognosis with high risk. Although the overuse of loop diuretics may induce hypovolemia, cardiac output reduction, and critical hypotension in severe AS, tolvaptan is characterized by its ability to help maintain hemodynamics and seems to be appropriate for use in heart failure caused by AS. Therefore, we retrospectively examined the effects and safety of tolvaptan use in patients with heart failure caused by severe AS.

Methods and Results: Ten patients with heart failure caused by severe AS were enrolled. Tolvaptan administration did not cause blood pressure decrease significantly, whereas urine volume increased significantly from 896±318 to 1322±502 mL/day (P<0.05). Although there was no statistical significance, functional classes tended to be improved. Blood tests indicated no worsening of kidney function and N-terminal pro-brain natriuretic peptide levels after the use of tolvaptan. Echocardiography also showed no hypovolemia and no worsening of aortic valve flow (18.3±3.8 to 15.5±5.5 cm/s, n.s).

Conclusions: Tolvaptan use in AS patients with heart failure is effective and safe before aortic valve intervention.

Summary: The Clinical Trial Act came into force in 2018 in Japan. A questionnaire survey was conducted with personnel at Kumamoto University Hospital engaged in research and development, to explore their perceptions of troubles and concerns about clinical research related to the Clinical Trial Act. We collected 127 comments about troubles and 149 about concerns. Text mining (co-occurrence network and hierarchical cluster analysis) was used to extract the characteristics or tendencies in these comments. The analysis extracted 18 key terms for troubles and 21 for concerns. Most troubles and concerns had to do with concrete examples of clinical research or protocols and biostatistics information. Our results emphasized the importance of clinical research support organizations, and suggested that appropriate workshops and information covering specific situations are necessary to perform clinical research under the new regime.

Summary: Adhesion is a common complication following surgical repair of flexor tendons, resulting in the restriction of tendon gliding. We investigated the effect of early exercise on adhesion formation. To create an adhesion model, the proximal region of the second phalanx of the third toe in 4-month-old White Leghorn chickens was cut. The gliding side of the flexor digitorum profundus was hemiresected and the bony floor was crushed to enhance adhesion formation. The resected area was fixed in an extended position for 1, 2, or 3 weeks. Following 1, 2, or 3 weeks of active exercise, the chickens were sacrificed and morphological changes in the adhesions were assessed. In the 1- and 2-week fixed groups, 1, 2, or 3 weeks of active exercise resulted in mesotenon-like adhesion that was elastic and had no effect on tendon gliding. However, in the 3-week fixed group, a mature adhesion remained with limited change and tendon gliding was inhibited even after 3 weeks of active exercise. Thus, we concluded that adhesions become more elastic with early exercise within 2 weeks after tendon repair, but that adhesions following tendon repair tend not to show any further elastic changes when exercise is started 3 weeks after the repair.

Summary: To improve component-placement accuracy in total knee arthroplasty, we developed two devices: an original extramedullary patient-specific guide for the femur and an original extramedullary universal guide for the tibia (EM-TIBIA). We also developed a new function in ZedView, a three-dimensional surgical assistive software, that provides the parameters necessary to install the EM-TIBIA. Compared with conventional manual methods based on X-ray two-dimensional images or ZedView, these newly developed devices function as an extramedullary intraoperative support guide in conjunction with ZedView, simplifying surgical procedures. We conducted a study to evaluate the efficacy and safety of the surgery using the new guides and software function. Nineteen patients underwent surgery. On the femoral side, the mean absolute difference of the installation alignment was within 3° for all parameters. On the other hand, on the tibial side, the mean absolute difference from the preoperative plan for the rotation was 5.26±5.30°. The proportion of patients whose difference fell within ±3° was 52.6% (95% confi dence interval: 28.9 to 75.6%), and did not meet the pre-specified criteria for efficacy (P=0.261). No serious adverse events were reported, and no excessive bleeding, thrombosis, infections, or intraoperative or postoperative fractures were noted. The two new guides can easily reproduce the preoperative plan as 3D intraoperative support jigs, but errors can occur on the tibia side due to soft tissue that is not recognized by CT, creating problems in installation accuracy.

Summary: Radiation-induced olfactory neuroblastoma (ONB) is an uncommon neoplasm that is generally associated with a poor prognosis. We experienced an unusual case of ONB in a patient who had received previous radiation therapy for extranodal NK/T-cell lymphoma 15 years previously. To our knowledge, this is the first report of a patient with radiation-induced ONB obtaining a complete response (CR) with radical re-irradiation alone. The purpose of this report is to discuss therapeutic strategies for radiation-induced ONB.

We report an unusual case of ONB suspected to be a radiation-induced neoplasm in a 33-year-old female who had received 30 Gy of irradiation for extranodal NK/T-cell lymphoma, nasal type (NTCL) 15 years earlier. In this case, the patient presented with nasal obstruction and frequent epistaxis. The patient was diagnosed with ONB based on left nasal biopsy findings. The surrounding normal tissues tolerance of nasal ONB radiation had to be limited, because the previously radiated NTCL was located adjacent to critical organs. We performed intensity modulated radiation therapy (IMRT), which could offer precise irradiation (60 Gy in 2 Gy daily fractions) while sparing critical tissues. The present case was treated with radiation therapy alone, whereas previously reported cases were treated with a combination of chemotherapy and radiation therapy. We treated radiation-induced OBN successfully with radical re-irradiation using IMRT alone and the patient has had no recurrence for 3 years.

Summary: The second largest intracranial specialization of the dura mater, the tentorium cerebelli, is a transverse fold that partially separates the cerebellum and cerebral hemispheres. During routine dissection of the posterior cranial fossa, a left-sided hypoplastic region of the tentorium cerebelli was observed. This fenestration was seen at the posterior portion of the tentorium as a posteromedial strip of tissue rising vertically to interface with the falx cerebri. Although isolated cases of tentorial hypoplasia have been reported in, for example, cases of Chiari II malformation, we believe isolated fenestration of this membrane is very rare, especially in the absence of the Chiari II malformation. The current case adds to the sparse literature on isolated tentorial defects and might be of interest to neurosurgeons or clinicians who review intracranial imaging.

Summary: The sciatic nerve typically follows its course through the greater sciatic foramen, below the piriformis muscle, and down the posterior aspect of the thigh, but many anatomical variations exist. Herein, we report an unusual relationship between the sciatic nerve and piriformis muscle in which the split common fibular nerve went through the piriformis and had a variant communication with the tibial nerve. To our knowledge, this anatomical variation has not been previously reported. Such variants are important to fully understand pathologies involving the sciatic nerve.