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Featured researches published by Shigeo Akagi.


Spine | 2003

Preventing C5 Palsy After Laminoplasty

Kunihiko Sasai; Takanori Saito; Shigeo Akagi; Isashi Kato; Hiroyuki Ohnari; Hirokazu Iida

Study Design. The incidences of postoperative C5 palsy between a group treated by a standardized diagnostic and surgical treatment and a control group treated by a different cervical laminoplastic technique were prospectively compared. Objective. To investigate the cause, risk factors, and prevention of C5 palsy after laminoplasty for cervical myelopathy. Summary of Background Data No one factor could predict postoperative C5 palsy, although postoperative C5 palsy is a clinically significant complication of cervical laminoplasty. Methods. One hundred eleven patients who underwent laminoplasty for cervical myelopathy were studied. Seventy-four patients who consulted two spinal surgeons (two of the authors) were placed into Group A. Thirty-seven patients who consulted the other two spinal surgeons (the other two authors) were placed into Group B. There were no statistical differences between the two groups for age at operation, gender, spinal disorders, preoperative neurologic severity, and length of the follow-up period. All patients in Group A underwent preoperative electromyographic testing. Patients with no electromyographic abnormalities underwent a standard midsagittal laminoplasty. Those with preoperative electromyographic abnormalities, reflecting a subclinical radiculopathy, underwent a modified en bloc laminoplasty with microcervical foraminotomy done at each level of the EMG abnormality. All Group B patients underwent midsagittal laminoplasty without preoperative electromyographic testing. Microcervical foraminotomy was performed for C5 root in 11 patients (14.9%) of Group A. Results. No patients in Group A and three patients (8.1%) in Group B experienced postoperative C5 palsy. This difference was statistically significant (P = 0.035, Fisher’s exact method). Conclusions. Electromyography is a sensitive predictor of postoperative C5 palsy after laminoplasty. This complication may be avoided by performing selective foraminotomy in addition to posterior central canal decompression. Preexisting subclinical C5 root compression is a cause of C5 palsy after posterior cervical decompression for myelopathy.


Journal of Spinal Disorders | 2000

Cervical curvature after laminoplasty for spondylotic myelopathy-involvement of yellow ligament, semispinalis cervicis muscle, and nuchal ligament

Kunihiko Sasai; Takanori Saito; Shigeo Akagi; Isashi Kato; Ryokei Ogawa

To assess the consequences of cervical laminoplasty on postoperative lordosis, a retrospective radiographic analysis of 31 patients undergoing laminoplasty for spondylotic myelopathy was completed. Special attention was paid to lordotic changes occurring at each level over more than 2 years. Preoperative lordosis remained unchanged with the patients wearing a cervical orthosis 1 week postoperatively. However the lordosis subsequently demonstrated a significant decrease in 87% of patients over an average of 3.1 years. Lordotic alignment at C2-C3 and C6-C7 before surgery significantly decreased in 81% and 58% of patients 1 week postoperatively, and 84% and 81% at last follow up, respectively, while lordotic alignment at other levels pre- and postoperatively did not significantly change. Loss of lordotic alignment was largely attributed to detachment of semispinalis cervicis muscle on C2 and nuchal ligament on C6/C7 with a posterior approach and/or section of yellow ligament at C2-C3.


Journal of Histochemistry and Cytochemistry | 1988

Localization of protein disulfide isomerase on plasma membranes of rat exocrine pancreatic cells.

Shigeo Akagi; Akitsugu Yamamoto; Tamotsu Yoshimori; Ryokei Ogawa; Yutaka Tashiro

We investigated immunocytochemically the ultrastructural localization of protein disulfide isomerase (PDI) in rat pancreatic exocrine cells by use of the post-embedding protein A-gold technique. We found that not only the endoplasmic reticulum (ER) and nuclear envelope but also the trans-Golgi cisternae, secretory granules, and plasma membranes were heavily labeled with gold particles. Labeling density of the gold particles in the rough ER and plasma membranes of the exocrine pancreatic cells was twofold and twentyfold greater, respectively, than that of hepatocytes. In the acinar lumen, amorphous material presumably corresponding to the secreted zymogens was also labeled with gold particles. These results suggest that in rat exocrine pancreatic cells a significant amount of PDI is transported to the plasma membrane and secreted to the acinar lumen.


Journal of Histochemistry and Cytochemistry | 1988

Distribution of protein disulfide isomerase in rat hepatocytes.

Shigeo Akagi; Akitsugu Yamamoto; Tamotsu Yoshimori; Ryokei Ogawa; Yutaka Tashiro

We investigated quantitatively the distribution of protein disulfide isomerase (PDI) in rat hepatocytes by immunocytochemistry using a post-embedding protein A-gold technique. In hepatocytes, gold particles were mainly localized in the intracisternal space of the rough and smooth endoplasmic reticulum (ER) and nuclear envelopes. Autolysosomes engulfing ER were occasionally densely labeled, especially in rat hepatocytes previously treated with leupeptin in vivo, suggesting that the autophagosome-autolysosome system may be an important route for degradation of PDI. A few gold particles were also found on the plasma membranes. Localization of gold particles on the other subcellular organelles, such as Golgi apparatus, peroxisomes, and nuclear matrix, was sparse and at the control level. The predominant localization of PDI on the intracisternal surface of the ER and nuclear envelope supports a potential role of PDI in the formation of disulfide bonds of nascent polypeptides, thus accelerating formation of the higher-order structure of secretory and membrane proteins and rendering the translocation process irreversible.


Clinical Rheumatology | 1997

The long-term results of ankle joint synovectomy for rheumatoid arthritis

Shigeo Akagi; H. Sugano; Ryokei Ogawa

SummaryThe clinical and radiological results of synovectomy for rheumatoid arthritis in the ankle joint were investigated in 20 ankles of 15 patients. The average follow-up period after synovectomy was 15 years, ranging from 10 to 25 years. The clinical evaluation at the time of follow-up, found that only two ankles showed recurrence of synovitis, and no patient complained of severe ankle pain disturbing the activities of daily life. During the period between the synovectomy and our investigation, no patients required further surgical procedures for their ankle joints. The radiological evaluation found that in approximately two-thirds of the cases, deterioration of the radiological grade, evaluated with Larsens criteria, had continued after synovectomy. There was no considerable radiological deterioration in the less-erosive subset patients, classified according to Ochis criteria (1). In the unilateral synovectomized cases, using the non-operated ankles as the natural-course control, osteoarthritic changes were predominant in the operated ankle joint, and the non-operated ankle demonstrated inflammatory disease changes. These results indicate that: (1) synovectomy for a rheumatoid ankle is still a preferred treatment, lessening the clinical symptom of persistent, marked synovial proliferation resistant to medical treatment. (2) Radiological deterioration continues after synovectomy in many cases. However, a radiogram demonstrates predominant osteoarthritic destruction, which indicates the natural course of rheumatoid destruction in the operated site could be altered by synovectomy.


Spine | 1999

External iliac artery occlusion in posterior spinal surgery.

Shigeo Akagi; Yugo Yoshida; Ishashi Kato; Kunihiko Sasai; Takanori Saito; Atsushi Imamura; Ryokei Ogawa

STUDY DESIGN Report of a case of external iliac artery occlusion occurring as a rare complication of lumbar posterior spinal surgery. OBJECTIVE To clarify the cause of this rare complication and recommend methods for preventing its recurrence. SUMMARY OF BACKGROUND DATA Several cases of central retinal artery occlusion after posterior spinal surgery have been reported, but there has been no reported case of external iliac artery occlusion after posterior spinal surgery. METHODS A 65-year-old woman who had a 32-year history of systemic lupus erythematosus underwent posterior decompression and spinal fusion for degenerative scoliosis. She was supported on a Hall frame during the operation. Three hours after surgery, paralysis and sensory impairment of the left leg and cyanosis of the toes of the left foot were noted. The popliteal, dorsalis pedis, and posterior tibial pulses were not palpable. Angiography showed complete occlusion of the external iliac artery, and emergency removal of the thrombus was performed. RESULTS One year later, neurologic symptoms were absent, and the leg vessels were normal. CONCLUSIONS Prolonged direct pressure on the inguinal region during posterior spinal surgery on a Hall frame may cause external iliac artery occlusion. Early recognition and adequate treatment can prevent serious sequelae.


Journal of Spinal Disorders & Techniques | 2005

Microsurgical posterior herniotomy with en bloc laminoplasty: alternative method for treating cervical disc herniation.

Kunihiko Sasai; Takanori Saito; Hiroyuki Ohnari; Tatsunori Yamamoto; Takashi Kasuya; Ei Wakabayashi; Shigeo Akagi; Hirokazu Iida

Objective: At the present time, the anterior cervical discectomy and fusion procedure is widely accepted for treating cervical disc herniation. Recently, however, several authors have reported new disease due to degeneration of an adjacent segment. On the other hand, posterior discectomy, which can preserve mobility at the affected disc level, has been considered risky and technically difficult, especially for central or paracentral disc herniation. We are performing a new surgical technique, microsurgical posterior herniotomy with en bloc laminoplasty, for patients with myelopathy and radiculomyelopathy caused by cervical disc herniation. Methods: Here, the surgical outcomes and radiographic changes were retrospectively investigated. Thirty patients (13 patients with myelopathy, 13 patients with radiculomyelopathy, and 4 patients with C5 dissociated motor loss) who underwent this procedure were reviewed. The average age was 50 years (range 31-70 years), and the average follow-up period was 28 months (range 12-76 months). Neurologic improvements were evaluated using the Japanese Orthopaedic Association (JOA) Scoring System as well as radicular pain and deltoid muscle power. Postoperative axial symptoms were scored, and radiographic changes were noted. Results: The mean JOA score improvement was 74.2% (range 27.3-100%). In all 13 patients, preoperative radicular pain completely resolved after surgery. Deltoid power (in cases of C5 dissociated motor loss) markedly increased postoperatively. Cervical lordosis significantly increased at the time of the last follow-up (P = 0.01). The postoperative axial symptom score significantly correlated with the numbers of opened laminae (P = 0.03). Conclusions: This technique was safe and effective. Radiographically, the range of motion in the cervical spine and at the affected disc levels was preserved. In the future, this surgical procedure can become an alternative method for cervical disc herniation treatment.


Orthopedics | 2000

Clinical and pathologic characteristics of lumbar disk herniation in the elderly.

Shigeo Akagi; Takanori Saito; Ishashi Kato; Kunihiko Sasai; Ryokei Ogawa

The clinical and pathologic characteristics of lumbar disk herniation in 23 elderly patients (15 men and 8 women) who required surgical treatment were investigated. Average age at surgery was 67.3 years, and average follow-up was 23 months. Preoperatively, the predominant symptom was severe unilateral leg pain, and 13 patients were nonambulatory because of leg pain. Operative treatment included wide laminectomy in 8, hemilaminectomy in 3, fenestration in 10, and osteoplastic laminectomy in 2 patients. Four (17%) patients had disk herniation at the L2-L3 or L3-L4 level. Sequestered herniation with or without migration was observed in 15 (65%) patients. Of 14 sequestered disk fragments examined histologically, 8 (57%) specimens contained cartilaginous or bony end plate with anulus fibrosus or nucleus pulposus. Postoperatively, results were rated as excellent in 11 patients and good in 12; no patient was rated as fair or poor. Severe leg pain affecting activities of daily life is a predominant symptom of disk herniation in the elderly. For patients in whom conservative treatment has failed, operative treatment should be considered. In lumbar disk herniation in the elderly, the incidence of cephalad and lateral herniation is higher than in younger patients. In addition, sequestered and migrated herniations including end plate are frequent.


Journal of Histochemistry and Cytochemistry | 1989

Distribution of protein disulfide isomerase in rat epiphyseal chondrocytes.

Shigeo Akagi; Akitsugu Yamamoto; Tamotsu Yoshimori; Ryokei Ogawa; Yutaka Tashiro

We investigated the intracellular distribution of protein disulfide isomerase (PDI) in rat epiphyseal chondrocytes by immunocytochemistry, using a post-embedding protein A-gold technique. Gold particles were localized primarily in the cisternal space of the rough endoplasmic reticulum (ER) and nuclear envelopes. The ER cisternae of the chondrocytes in all the differentiating epiphyseal zones--resting, proliferative, pre-hypertrophic, and hypertrophic--were equally and highly labeled. The labeling density of the cisternal space of the dilated ER, probably reflecting marked accumulation of secretory proteins such as procollagen, was always higher than that of the non-dilated ER. In the dilated cisternal space, gold particles were freely and evenly distributed, without preferential binding to the luminal surface of the ER membranes. We suggest that PDI catalyzes the formation of disulfide bonds of various secretory proteins, perhaps type II procollagen, in the cisternal space of the ER in epiphyseal chondrocytes. The exclusive localization of gold particles in the cisternal space of the ER and nuclear envelopes and the lack of gold particles in the Golgi apparatus, including cis-Golgi cisternae, indicate that PDI is an ER-soluble protein in the chondrocytes and is presumably sorted out in some pre-Golgi compartment and not transported to the Golgi apparatus.


Spine | 1995

Maffucci's syndrome involving hemangioma in the cervical spine

Shigeo Akagi; Takanori Saito; Ryokei Ogawa

Study Design This is a case report of a patient with Maffuccis syndrome, with hemangioma located in the cervical spine causing paraplegia. Objective To present a rare case of Maffuccis syndrome with hemangioma located in the cervical spine, and to discuss the incidence and treatment of hemangioma located in the central nerve system in Maffuccis syndrome. Summary of Background Data Maffuccis syndrome is characterized by enchondromatosis and soft tissue hemangioma. Hemangioma usually is located in the subcutaneous tissue and rarely in the mucosa and visceral organs. There have been no reports in the literature on the incidence of hemangioma in the cervical spine occurring with Maffuccis syndrome. Methods The patient was an 11-year-old girl, who complained of muscle weakness of the upper extremity and gait disturbance. After clinical and radiologic evaluation, the patient was diagnosed as having dumbbell tumor of the cervical spine associated with Maffuccis syndrome. Results The tumor was successfully excised after selective angiography and embolization of the feeding artery from the ascending cervical artery and costocervical trunk, the result being excellent neurologic recovery for the patient. Histologic study showed the tumor was hemangioma similar to the red-blue tissue tumor in the hand. Conclusion The possibility of hemangioma being localized in the spinal column, as well as in the subcutaneous tissue, mucosa, and visceral organ, should be considered in cases of Maffuccis syndrome.

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Ryokei Ogawa

Kansai Medical University

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Takanori Saito

Kansai Medical University

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Kunihiko Sasai

Kansai Medical University

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Hiroyuki Ohnari

Kansai Medical University

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Yoshitaka Toda

Kansai Medical University

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Yutaka Tashiro

Kansai Medical University

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