Fumio Hayashi

Intramedullary schwannoma with calcification of the epiconus

BACKGROUND CONTEXT There have been few reports on intramedullary ancient schwannoma. Schwann cells are generally present in the nerve root, not in the spinal cord. Thus, intramedullary schwannomas are rare, and in most cases there is cyst formation without calcification. PURPOSE To report a patient with intramedullary ancient schwannoma at the epiconus together with a review of the previously published cases. STUDY DESIGN Case report. PATIENT A 78-year-old woman. METHODS Retrospective case review. DESCRIPTION OF THE CASE A 78-year-old woman had presented with severe weakness of the lower extremities, increased patellar reflex, and sensory disturbance of the entire lower extremities. Magnetic resonance imaging showed a tumorous mass in the intramedullary region of epiconus at T11-L1, and computed tomography revealed calcification in the tumor. She underwent total resection of the tumor. Histopathological findings were consistent with the diagnosis of ancient schwannoma. After the operation, although lower extremities weakness and sensory disturbance deteriorated transiently, lower leg pain disappeared. At the final follow-up of 10 months after the operation, lower leg pain did not relapse. CONCLUSION We reported a rare case presenting epiconus syndrome due to intramedullary ancient schwannoma, which should be considered for the differential diagnosis of a tumor that shows calcification.

Distance Between the Anterior Distal Tibial Edge and the Anterior Tibial Artery in Distraction and Nondistraction During Anterior Ankle Arthroscopy: A Cadaveric Study:

Background: Anterior ankle arthroscopy is widely applied for various osteoarthropathies. However, distraction of the ankle may put the anterior tibial artery (ATA) at risk of injury during the procedure. The purpose of this study was to assess the difference in the distance between the anterior distal tibial edge and the ATA in distraction and nondistraction of the ankle with joint space expansion by saline injection into the joint. Methods: Eight whole fresh-frozen cadaveric feet (mean age 78.9 years) were used. Barium sulfate suspension was injected into the popliteal artery of each specimen, and the distance from 3 aspects of the anterior distal tibial edge to the ATA was measured to evaluate the possibility of damage to the ATA based on computed tomography (CT) scans, in ankle distraction and nondistraction, using a traction device developed for reproducible ankle positioning inside the CT scanner. Results: The distance between the ATA and the most proximal, middle, and distal parts of the anterior distal tibial edge was 0.5 mm, 3.9 mm, and 7.4 mm, respectively, without saline injection, and 3.7 mm, 7.2 mm, and 11.6 mm, respectively, with saline injection, in nondistraction. The distance was 2.2 mm, 5.9 mm, and 9.8 mm, respectively, with 5-kg distraction, and 1.7 mm, 5.1 mm, and 8.8 mm, respectively, with 10-kg distraction, both with saline injection, respectively. Conclusion: The distance between the anterior distal tibial edge and the ATA with joint space expansion by saline injection into the joint increased, and that distance in distraction of the ankle decreased during anterior arthroscopic surgery. Clinical Relevance: The anatomic relationship of the ATA to its surrounding structures may be at more risk without saline injection or with distraction during anterior ankle arthroscopy.

A new concept of transforaminal ventral facetectomy including simultaneous decompression of foraminal and lateral recess stenosis: Technical considerations in a fresh cadaver model and a literature review

Percutaneous endoscopic surgery for the lumbar spine, which was established in the last decade, requires only an 8-mm skin incision and causes minimal damage to the paravertebral muscles; thus, it is considered to be a minimally invasive technique for spinal surgery. It has been used to perform percutaneous endoscopic discectomy via two main approaches: the TF approach is a posterolateral one through the intervertebral foramen and can be done under local anesthesia; the IL approach is a more traditional one through the interlaminar space and is difficult to perform under local anesthesia. Recently, these techniques have been applied for lumbar spinal stenosis (LSS), the TF method for foraminal stenosis under local anesthesia, and the IL method for central and lateral recess stenosis under general anesthesia. In this study, using a fresh human cadaver model, we performed simultaneous decompression of the lateral recess and foraminal stenosis at L4-5 using the TF approach. Computed tomography confirmed enlargement of the lateral recess and intervertebral foramen. This technique, which can be performed under local anesthesia, should benefit elderly patients with LSS and poor general condition due to multiple comorbidities. Finally, we introduce the concept of percutaneous transforaminal ventral facetectomy using a spinal percutaneous endoscope. J. Med. Invest. 64: 1-6, February, 2017.

Direction and location of the nutrient artery to the fifth metatarsal at risk in osteotomy for bunionette

BACKGROUND The aims of this study were to identify the artery feeding the fifth metatarsal and determine how bunionette osteotomy could injure this vessel. METHODS The nutrient artery entering the fifth metatarsal was investigated in 10 adult cadaveric lower limbs by barium injection and enhanced computed tomography. RESULTS The nutrient artery entered the medial aspect of the fifth metatarsal around the junction of the middle and proximal thirds obliquely from a distal direction (mean angle 36°) in the coronal plane in all cases; in the axial plane, the point of entry and direction of the artery was medial-plantar (mean angle 49°). CONCLUSIONS This report revealed direction and location of the nutrient artery entering the fifth metatarsal.

Examination of the Origin and Branching Direction of the Anterior Medial Malleolar Artery From the Anterior Tibial Artery: A Cadaveric Study

Background. This study characterized the anterior medial malleolar artery (AMMA) branching from the anterior tibial artery (ATA) to identify problems in anterior ankle arthroscopy possibly contributing to injury to the AMMA. Methods. Barium was injected into 12 adult cadaveric feet via the external iliac artery and the origin and branching direction of the AMMA were identified on computed tomography. Results. The AMMA originated from the level of the ankle joint and below and above the ankle joint line (AJL) in 4 (33.3%), 6 (50.0%), and 1 (8.3%) specimen, respectively. Mean distance from the AJL to the branching point of the AMMA on the sagittal plane was 2.5 mm distal to the AJL. Mean angle between the distal longitudinal axis of the ATA and AMMA was 83.2°. Conclusions. This study established the origin and branching of the AMMA from the ATA. The AMMA should be examined carefully during ankle arthroscopy. Levels of Evidence: Level IV: Cadaveric study

Comparison of Ankle Joint Visualization Between the 70° and 30° Arthroscopes: A Cadaveric Study

Ankle arthroscopy is an important diagnostic and therapeutic tool. Arthroscopic ankle surgery for anterior ankle impingement or osteochondral lesions (OCLs) is mostly performed with a 30° arthroscope; however, visualization of lesions is sometimes difficult. This study sought to compare ankle joint visualization between 70° and 30° arthroscopes and clarify the effectiveness of 70° arthroscopy. Standard anterolateral and anteromedial portals were placed with 4-mm 70° or 30° angled arthroscopes in a fresh 77-year-old male cadaveric ankle. The medial ligament and surrounding tissue were dissected via a medial malleolar skin incision. Kirschner wires were inserted into the distal tibia anterior edge; 5-mm diameter OCLs were created on the medial talar gutter anteriorly, midway, and posteriorly. The talar dome and distal tibia anterior edge were visualized using both arthroscopes. The 70° arthroscope displayed the anterior edge of the distal tibia immediately in front of the arthroscope, allowing full visualization of the posterior OCL of the medial talar gutter more clearly than the 30° arthroscope. This study revealed better ankle joint visualization with the 70° arthroscope, and may enable accurate, safe, and complete debridement, especially in treatment of medial talar gutter posterior OCLs and removal of anterior distal tibial edge bony impediments. Levels of evidence: Level IV, Anatomic study

Percutaneous full endoscopic lumbar foraminoplasty for adjacent level foraminal stenosis following vertebral intersegmental fusion in an awake and aware patient under local anesthesia: A case report

Percutaneous endoscopic surgery for the lumbar spine has become established in the last decade. It requires only an 8 mm skin incision, causes minimal damage to the paravertebral muscles, and can be performed under local anesthesia. With the advent of improved equipment, in particular the high-speed surgical drill, the indications for percutaneous endoscopic surgery have expanded to include lumbar spinal canal stenosis. Transforaminal percutaneous endoscopic discectomy has been used to treat intervertebral stenosis. However, it has been reported that adjacent level disc degeneration and foraminal stenosis can occur following intervertebral segmental fusion. When this adjacent level pathology becomes symptomatic, additional fusion surgery is often needed. We performed minimally invasive percutaneous full endoscopic lumbar foraminoplasty in an awake and aware 50-year-old woman under local anesthesia. The procedure was successful with no complications. Her radiculopathy, including muscle weakness and leg pain due to impingement of the exiting nerve, improved after the surgery. J. Med. Invest. 64: 291-295, August, 2017.

Role of Epiligament in Ligamentum Flavum Hypertrophy in Patients with Lumbar Spinal Canal Stenosis:a Pilot Study

Ligamentum flavum (LF) hypertrophy is one of the main factors of lumbar spinal canal stenosis (LSCS). The primary object of this study is to clarify the existence of epiligament in the LF and its role in hypertrophy, and to develop an LF hypertrophy animal model. A cadaveric spine from a 30-year-old man was used to investigate the existence of epiligament in LF. Five LF samples from LSCS patients were obtained to evaluate hypertrophied LF. To create a rat model, we destabilized the lumbar spine. Each LF was sagittally cut for histological evaluation. The epiligament was clearly evident in normal LF specimens, which stained pink on Elastica van Gieson and green on Masson Trichrome. One layer was observed on the dural side and another on the dorsal side of the LF. LSCS patients had an enlarged dorsal epiligament, at around 30 times that of the regular thin epiligament on the dural side. The destabilized rat model showed an enlarged dorsal epiligament, with a mean thickness 8-fold that of the control. LF hypertrophy may be due to enlargement of the dorsal epiligament. Mechanical loading of the LF is an important factor for inducing hypertrophy in the rat model. J. Med. Invest. 65:85-89, February, 2018.

Successful Endoscopic Surgery for L5 Radiculopathy Caused by Far-Lateral Disc Herniation at L5-S1 and L5 Isthmic Grade 2 Spondylolisthesis in a Professional Baseball Player

ABSTRACT Background: We report the case of a professional baseball player who had severe leg pain due to lumbar lateral disc herniation at L4-5 and isthmic spondylolisthesis at L5 (double crash syndrome). For early recovery to competitive level, we performed minimally invasive endoscopic decompression surgery without fusion. There are few reports to discuss the usefulness of minimally invasive treatment for top athletes. Methods: A 29-year-old professional baseball player who played catcher was referred to us with a complaint of right leg pain. The previous doctor diagnosed far-lateral disc herniation and Grade 2 isthmic spondylolisthesis and recommended arthrodesis at L5-S1 as treatment for both pathologies. Radiological imaging showed that the right L5 nerve root was impinged by the 2 lumbar disorders, namely, far-lateral disc herniation and a ragged edge around a pars defect. We had taken into account the patients occupation and his wish to avoid a lengthy sick leave, and we had performed endoscopic decompression surgery during the offseason. The far-lateral disc herniation at L5-S1 was removed under local anesthesia by percutaneous endoscopic discectomy, after which the ragged edge at the pars defect was removed under general anesthesia using a microendoscopic discectomy system. Given that the patient did not have any low back pain, arthrodesis was not considered. Results: The leg pain resolved after surgery. The following year (2015), the patient resumed playing baseball from the beginning of the season and played in 41 games. In the 2016 season, he played in 71 games without any symptoms. No further slippage was observed at radiological follow up 1 year after the surgery. Conclusions: Minimally invasive endoscopic surgery is an option for radiculopathy in very active patients who need an early return to their previous level of physical activity.

Anatomic Study of Anterior and Posterior Ankle Portal Sites for Ankle Arthroscopy in Plantarflexion and Dorsiflexion: A Cadaveric Study in the Japanese Population

ABSTRACT Arthroscopy is an important and minimally invasive diagnostic and therapeutic tool. However, the risk of injury to the neurovascular structures around the portals exists during arthroscopy of the ankle. In the present study, we measured the distance between each portal and the adjacent neurovascular structures with the foot in plantarflexion and dorsiflexion in the Japanese population. Standard anterolateral (AL), anteromedial, posterolateral (PL), and posteromedial portal positions were identified in 6 fresh adult cadaveric feet. The skin was dissected from the underlying tissue to visualize the adjacent neurovascular structures as noninvasively as possible. The superficial peroneal nerve was the structure closest to an anterior (i.e., AL) portal (3.2 ± 4.2 and 8.3 ± 3.9 mm in plantarflexion and 5.2 ± 4.3 and 10.8 ± 4.1 mm in dorsiflexion), followed by the saphenous nerve and great saphenous vein (SpV). The distance from the superficial peroneal nerve to the AL portal and from the saphenous nerve and great SpV to the anteromedial portal increased significantly with dorsiflexion and decreased significantly with plantarflexion. The sural nerve was the structure closest to the posterior (i.e., PL) portal (10.4 ± 4.8 mm in plantarflexion and 8.5 ± 3.9 mm in dorsiflexion), followed by the lesser SpV. The distance from the sural nerve, saphenous nerve, and lesser SpV to the PL portal and from flexor hallucis longus, posterior tibial artery, and tibial nerve to the posteromedial portal increased significantly in plantarflexion and decreased significantly in dorsiflexion. These findings could help to prevent damage to the neurovascular structures during ankle arthroscopy. Level of Clinical Evidence: 5