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  • Author or Editor: Ryu Kurokawa x
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Shinji Yamamoto, Ryu Kurokawa and Phyo Kim

Object

Regional blood flow is decreased in experimental models of chronic spinal cord compression, and the alteration presumably contributes to the development of myelopathy. Cilostazol (Otsuka Pharmaceuticals Co.), a selective Type III phosphodiesterase inhibitor, has been shown to be neuroprotective in cerebral hypoperfusion animal models and clinically effective in preventing the recurrence of cerebral infarction. To investigate the neuroprotective effect of cilostazol on cervical spondylotic myelopathy, the preventive effect against progressive motor dysfunction and the loss of anterior horn motor neurons were assessed using a chronic cord compression model in rats.

Methods

To produce chronic cervical cord compression in male Wistar rats, thin polyurethane sheets (3 × 5 × 0.7 mm) that gradually expand over 48–72 hours by absorbing water were implanted under the C5–6 laminae. In sham operations, the sheets were momentarily placed and then immediately removed. This model has been shown to reproduce characteristic features of clinical cervical myelopathy, with progressive motor disturbances after a latency period and insidious neuronal loss preceding the onset of symptoms. In the treatment group, cilostazol (30 mg/kg/day) was orally administered to the rats once a day, starting the day after surgery and continuing through the entire observation period of 25 weeks. In the control group, vehicle solution was administered under the same protocol. Changes in motor function were monitored by measuring bilateral forepaw grip strength and the duration of forced running on a treadmill. Twenty-five weeks after surgery, cervical spinal cords were examined histopathologically.

Results

Cilostazol preserved both forepaw grip strength and forced running capability. The drug also preserved anterior horn motor neurons in the C5–6 spinal cord segment, which diminished in number in the untreated chronic compression group. The drug decreased the number of TUNEL-positive apoptotic cells.

Conclusions

These results indicate that cilostazol is neuroprotective in the chronically compressed cervical cord and is potentially useful in the treatment of cervical spondylotic myelopathy.

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Phyo Kim, Hidetoshi Murata, Ryu Kurokawa, Yoshiyuki Takaishi, Keizo Asakuno and Toshiki Kawamoto

Object

Laminoplasty has been used to expand the cervical spinal canal, based on the belief that reconstruction of the laminae preserves musculoskeletal function. The true efficacy of laminoplasty for maintaining spinal alignment, stability, and flexibility, however, remains to be proven. The authors have developed a new method, myoarchitectonic spinolaminoplasty (MSLP), which preserves all of the nuchal muscles and reconstitutes all of the musculoskeletal couplings to the posterior elements of the vertebrae. The details of this technique are described, and the efficacy of the technique in conserving muscle volume, alignment, and motion, as well as in preventing postoperative musculoskeletal discomfort, is assessed.

Methods

The authors' previous midline-splitting laminoplasty procedure, which utilized a hydroxyapatite (HA) implant as a substitute for the spinous process, was improved. Detachment of the muscles is avoided with this new technique by cutting inside the spinous process. The bone–muscle flaps are affixed to the HA spinous process. Radiographs, computed tomography scans, and neurological evaluations obtained at the 1-year follow-up in the groups of consecutive patients assessed immediately prior to and after the modification of the previous technique (the control and the MSLP groups, respectively) were analyzed and compared.

Results

The HA bone constructs became integrated due to osteoconduction. The cross-sectional area of the semispinalis capitis, semispinalis cervicis, and multifidus muscles remained significantly larger in the MSLP group. Slight attenuation in lordosis was observed in the control group, but was prevented in the MSLP group. Range of motion was somewhat restricted in the MSLP group, but the incidence of neck pain and shoulder strain was significantly reduced.

Conclusions

The new MSLP method was effective in preserving the volume and functions of the nuchal musculature and helping to minimize postoperative musculoskeletal complaints.

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Keisuke Takai, Toshiki Endo, Takao Yasuhara, Toshitaka Seki, Kei Watanabe, Yuki Tanaka, Ryu Kurokawa, Hideaki Kanaya, Fumiaki Honda, Takashi Itabashi, Osamu Ishikawa, Hidetoshi Murata, Takahiro Tanaka, Yusuke Nishimura, Kaoru Eguchi, Toshihiro Takami, Yusuke Watanabe, Takeo Nishida, Masafumi Hiramatsu, Tatsuya Ohtonari, Satoshi Yamaguchi, Takafumi Mitsuhara, Seishi Matsui, Hisaaki Uchikado, Gohsuke Hattori, Nobutaka Horie, Hitoshi Yamahata and Makoto Taniguchi

OBJECTIVE

Spinal arteriovenous shunts are rare vascular lesions and are classified into 4 types (types I–IV). Due to rapid advances in neuroimaging, spinal epidural AVFs (edAVFs), which are similar to type I spinal dural AVFs (dAVFs), have recently been increasingly reported. These 2 entities have several important differences that influence the treatment strategy selected. The purposes of the present study were to compare angiographic and clinical differences between edAVFs and dAVFs and to provide treatment strategies for edAVFs based on a multicenter cohort.

METHODS

A total of 280 consecutive patients with thoracic and lumbosacral spinal dural arteriovenous fistulas (dAVFs) and edAVFs with intradural venous drainage were collected from 19 centers. After angiographic and clinical comparisons, the treatment failure rate by procedure, risk factors for treatment failure, and neurological outcomes were statistically analyzed in edAVF cases.

RESULTS

Final diagnoses after an angiographic review included 199 dAVFs and 81 edAVFs. At individual centers, 29 patients (36%) with edAVFs were misdiagnosed with dAVFs. Spinal edAVFs were commonly fed by multiple feeding arteries (54%) shunted into a single or multiple intradural vein(s) (91% and 9%) through a dilated epidural venous plexus. Preoperative modified Rankin Scale (mRS) and Aminoff-Logue gait and micturition grades were worse in patients with edAVFs than in those with dAVFs. Among the microsurgical (n = 42), endovascular (n = 36), and combined (n = 3) treatment groups of edAVFs, the treatment failure rate was significantly higher in the index endovascular treatment group (7.5%, 31%, and 0%, respectively). Endovascular treatment was found to be associated with significantly higher odds of initial treatment failure (OR 5.72, 95% CI 1.45–22.6). In edAVFs, the independent risk factor for treatment failure after microsurgery was the number of intradural draining veins (OR 17.9, 95% CI 1.56–207), while that for treatment failure after the endovascular treatment was the number of feeders (OR 4.11, 95% CI 1.23–13.8). Postoperatively, mRS score and Aminoff-Logue gait and micturition grades significantly improved in edAVFs with a median follow-up of 31 months.

CONCLUSIONS

Spinal epidural AVFs with intradural venous drainage are a distinct entity and may be classified as type V spinal vascular malformations. Based on the largest multicenter cohort, this study showed that primary microsurgery was superior to endovascular treatment for initial treatment success in patients with spinal edAVFs.