Nobuo Arima

Differences between subtotal corpectomy and laminoplasty for cervical spondylotic myelopathy.

Objective:This study aimed to obtain guidelines for choosing between subtotal corpectomy (SC) and laminoplasty (LP) by analysing the surgical outcomes, radiological changes and problems associated with each surgical modality.Study Design:A retrospective analysis of two interventional case series.Setting:Department of Orthopaedic Surgery, Kagawa University, Japan.Methods:Subjects comprised 34 patients who underwent SC and 49 patients who underwent LP. SC was performed by high-speed drilling to remove vertebral bodies. Autologous strut bone grafting was used. LP was performed as an expansive open-door LP. The level of decompression was from C3 to C7. Clinical evaluations included recovery rate (RR), frequency of C5 root palsy after surgery, re-operation and axial pain. Radiographic assessments included sagittal cervical alignment and bone union.Results:Comparisons between the two groups showed no significant differences in age at surgery, preoperative factors, RR and frequency of C5 palsy. Progression of kyphotic changes, operation time and volumes of blood loss and blood transfusion were significantly greater in the SC (two- or three-level) group. Six patients in the SC group required additional surgery because of pseudoarthrosis, and four patients underwent re-operation because of adjacent level disc degeneration. In the LP group, the problem of elimination of postoperative axial symptoms remains to be solved.Conclusions:The merit of SC is the low frequency of axial symptoms. One-level SC can be considered to have similar degree of invasiveness as LP. Compared with SC, LP is more suitable for elderly patients with multilevel stenosis.

Relationship between muscle oxygenation and electromyography activity during sustained isometric contraction

The purpose of this study was to clarify the relationship between electromyography (EMG) spectrum changes and muscle oxygenation measured by near‐infrared time‐resolved spectroscopy (TRS). Each subject performed sustained isometric knee extension at 50% of the maximal voluntary contraction load for 1 min. Surface EMG and TRS were simultaneously recorded from the right vastus lateralis muscle. Mean power frequency (MPF) of the power spectrum was calculated every 5 s during isometric contraction using fast Fourier transform, and decrease in the slope of MPF for 1 min was calculated using the least squares method. The maximal changes in oxygenated haemoglobin and myoglobin (Oxy Hb/Mb) and in deoxygenated haemoglobin and myoglobin (Deoxy Hb/Mb) from pre‐contraction values of 1 min were calculated. There were significant relationships between the decrease in the slope of MPF and the maximal changes in Oxy Hb/Mb and Deoxy Hb/Mb (P < 0·05). These findings suggested that changes in Oxy Hb/Mb and Deoxy Hb/Mb indicate muscle fatigue assessed by EMG.

Mechanism of intramedullary high intensity area on T2‐weighted magnetic resonance imaging in osteoid osteoma: A possible role of COX‐2 expression

To study the mechanism and pathophysiology of the development of intramedullary high intensity areas on T2‐weighted magnetic resonance images (MRI) in cases of osteoid osteoma, we examined the expression of cyclooxygenase‐2 (COX‐2) in the nidus and surrounding bone tissues. In all six cases showing a marked intramedullary high intensity area adjacent to the nidus before surgery, neoplastic osteoblasts inside the nidus showed strong and diffuse COX‐2 immunoreactivity. On the other hand, the osteoblasts rimming the surrounding reactive bone were COX‐2 negative. In two cases examined by reverse transcription–polymerase chain reaction (RT–PCR), COX‐2 mRNA was detected in abundance in the nidus. Histologically, vascular dilatation together with intramedullary edema was observed in all cases, which was probably reflected as a high intensity area on T2‐weighted MRI. From our study, a high level of COX‐2 expression in neoplastic osteoblasts in the nidus of osteoid osteomas may cause the secondary changes depicted by MRI.

Lipofibromatous hamartoma of nerve in the foot.

A case of lipofibromatous hamartoma in the foot is described. This tumor‐like lesion commonly occurs in the hands, wrists and forearms of young persons. The median nerve is affected in the great majority of cases. Only very rarely, however, is it found in the nerves of the foot. It is believed that the present study is the seventh reported case of lipofibromatous hamartoma in the foot, and is the first case reported in Japan. A review shall be made of the six reported cases in the foot.

Clinical outcomes of percutaneous curettage and continuous irrigation for pyogenic spondylitis.

BACKGROUND Several recent studies have reported percutaneous curettage and continuous irrigation as effective treatments for pyogenic spondylitis. However, factors affecting the normalization of CRP levels remain unclear. This retrospective study investigated the clinical outcomes of percutaneous curettage and continuous irrigation for pyogenic spondylitis, and factors affecting the duration until normalization of CRP levels. METHODS Subjects comprised 16 patients who underwent percutaneous curettage and continuous irrigation for pyogenic spondylitis. Patients were divided into 3 groups according to duration from surgery until normalization of CRP levels to <or=0.20 mg/dL: early (n = 5), <or=2 weeks; middle (n = 6), <or=6 weeks; and delayed (n = 5), >6 weeks. Clinical and radiographic findings were compared between groups. RESULTS Japanese Orthopaedic Association score was improved in all patients within 2 weeks after surgery. Preoperative CRP level was lower in the early group (0.55 +/- 0.27 mg/dL) compared with the middle (2.63 +/- 1.84 mg/dL; P < .05) and delayed groups (7.59 +/- 10.44; P < .05). Duration of irrigation was shorter in the delayed group (10.7 +/- 3.7 days) compared with the early (15.6 +/- 2.0 days; P < .05) and middle groups (15.5 +/- 3.0 days; P < .05). Findings on MRI improved within 2 months in the early and middle groups. CONCLUSIONS This treatment is minimally invasive and useful in patients with pyogenic spondylitis. Lower CRP level before surgery and longer duration of irrigation may reduce the duration to normalization of CRP level.

Percutaneous curettage and continuous irrigation for MRSA lumbar spondylodiscitis: a report of three cases.

There has been a recent increase in pyogenic spondylitis caused by methicillin-resistant Staphylococcus aureus (MRSA) associated with an increasing number of compromised patients. As long as serious paralysis is absent, we recommend percutaneous curettage and continuous irrigation as an effective treatment for MRSA lumbar spondylodiscitis. Under local anesthesia, the affected lumbar discs were curetted using percutaneous nucleotomy, and tubes were placed for continuous irrigation. The period of continuous irrigation was generally 2 weeks. Infection was controlled after one procedure in two cases and after two procedures in one case. Postoperative radiography and magnetic resonance imaging (MRI) showed callus formation, normalized signal intensity in vertebral bodies, and regression of abscesses. Open surgery under general anesthesia has been considered risky in patients with poor performance status or old age. The present method, which is an application of needle biopsy, can be performed under local anesthesia and is minimally invasive.

Percutaneous Discectomy—Continuous Irrigation and Drainage for Tuberculous Lumbar Spondylitis: A Report of Two Cases

Percutaneous curettage and continuous irrigation were performed for definitive diagnosis and treatment of tuberculous (TB) lumbar spondylitis. Under local anaesthesia, affected lumbar discs were curetted using a procedure of percutaneous nucleotomy, and in-tube and the out-tube were placed for continuous irrigation. The period of continuous irrigation was 12–16 days. Mycobacterium tuberculosis was demonstrated in case 1 by culture and PCR, whereas histology showed tuberculous lesion with caseous necrosis in both cases. Postoperative MRI showed markedly reduced abscesses after 3 months in both cases. The signal intensity in vertebral bodies was improved. In Case 2, CT observations showed remodeling over time in the vertebral body cavities. This method is advantageous in that although minimally invasive, it achieves identification of pathogenic bacteria and treatment simultaneously. This surgical procedure is expected to prove effective for both TB and pyogenic spondylitis.