Search Results

You are looking at 1 - 6 of 6 items for

  • Author or Editor: Kanichiro Wada x
  • Refine by Access: all x
Clear All Modify Search
Restricted access

Atsushi Ono, Toru Yokoyama, Takuya Numasawa, Kanichiro Wada, and Satoshi Toh

✓Excellent results from laminoplasty for cervical spinal myelopathy have been reported in many studies. Nevertheless, C-5 nerve root palsy or axial pain such as neck and shoulder pain after laminoplasty are known postoperative complications. To the authors' knowledge, dural damage from dislocation of the hydroxyapatite intraspinous spacer due to absorption of the tip of the spinous process has not been reported. Two cases of dural damage from dislocation of the hydroxyapatite intraspinous spacer after laminoplasty are described.

Radiographs, computed tomography myelography, and magnetic resonance (MR) imaging revealed the dislocation of the hydroxyapatite intraspinous spacer, the absorption of the tip of the spinous process, and dural sac compression due to the hydroxyapatite intraspinous spacer. In one patient, the MR imaging studies revealed liquorrhea around the hydroxyapatite intraspinous spacers. Both patients underwent removal of the hydroxyapatite intraspinous spacer and attained good neurological recovery.

In patients with dislocation of the hydroxyapatite intraspinous spacer associated with absorption of the tip of the spinous process after spinous process–splitting laminoplasty, each case should be evaluated for aggravating symptoms of myelopathy, dural damage, and liquorrhea around the spacer.

Restricted access

Atsushi Ono, Futoshi Suetsuna, Tomoyuki Irie, Toru Yokoyama, Takuya Numasawa, Kanichiro Wada, and Satoshi Toh

Object

Previous reports of redundant nerve roots (RNRs) of the cauda equina have been limited to evaluations based on myelography. Neither the imaging nor the clinical features of RNRs in relation to magnetic resonance (MR) imaging have been elaborated. The MR imaging characteristics of RNRs were evaluated using the Japanese Orthopaedic Association score before and after the surgery.

Methods

There were 44 patients with L4–5 spondylolisthesis in which a complete blockage was demonstrated on myelography. All patients underwent posterior L4–5 interbody fusion. Based the myelographic and MR imaging findings, the patients were stratified into the following three groups: RNRs recognized on both myelographic and MR imaging (Group A); RNRs recognized on myelography but not very evident on MR imaging (Group B); and RNRs not recognized on either myelographic or MR imaging (Group C). Among these three groups, pre- and postoperative clinical symptoms were compared.

Results

There were 16 patients in Group A, 14 in Group B, and 14 in Group C. In terms of preoperative clinical symptoms, there was a significant difference between Groups A and C in the incidence of leg pain and tingling sensation. Significant differences were also noted between Groups A and C and between Groups B and C in ambulatory ability. Evaluation of postoperative clinical symptoms showed a significant difference between Groups A and C in ambulatory ability.

Conclusions

Patients with MR imaging evidence of RNRs presented with more severe clinical symptoms. It is believed that the RNR features derived from MR images represent important findings.

Restricted access

Atsushi Ono, Futoshi Suetsuna, Kazumasa Ueyama, Toru Yokoyama, Shuichi Aburakawa, Kazunari Takeuchi, Takuya Numasawa, Kanichiro Wada, and Satoshi Toh

Object

There have been few reports about the cervical spinal motion in patients with Chiari malformation Type I (CM-I) associated with syringomyelia. To investigate this phenomenon, the relationship between the preoperative cervical range of motion (ROM) and the stage of cerebellar tonsillar descent as well as the cervical ROM before and after foramen magnum decompression (FMD) were evaluated.

Methods

Thirty patients who had CM-I associated with syringomyelia and who underwent FMD participated in the study. The ROM and lordosis angle of the cervical spine were measured on x-ray films. In addition, the relationship between preoperative degree of cerebellar tonsillar descent and the ROM between the levels of the occiput (Oc) and C2 was investigated.

Results

The mean flexion–extension ROM at Oc–C2 was 15.5° before and 14.1° after surgery, and the mean flexion–extension ROM of C2–7 was 55.1° before and 52.8° after surgery. The mean pre- and postoperative lordosis angles at C2–7 were 16.8 and 19.1°, respectively. There was no significant difference between the values measured before and after surgery. There was no correlation between the degree of cerebellar tonsillar descent and the ROM at Oc–C2.

Conclusions

Foramen magnum decompression is an excellent surgical technique that has no effect on the postoperative cervical ROM and cervical alignment.

Restricted access

Atsushi Ono, Futoshi Suetsuna, Kazumasa Ueyama, Toru Yokoyama, Shuichi Aburakawa, Takuya Numasawa, Kanichiro Wada, and Satoshi Toh

Object

The clinical characteristics of pediatric scoliosis associated with syringomyelia have been reported in previous studies, but scoliosis associated with syringomyelia in adults is rarely treated, and there is a paucity of detailed studies. In the present study of adult syringomyelia associated with Chiari malformation Type I, the authors investigated the relationships among the syrinx, scoliosis, and neurological data.

Methods

The population was composed of 27 patients (≥ 20 years of age) who underwent foramen magnum decompression for the treatment of syringomyelia. The patients were divided into two groups: those with scoliosis of 10° or more (Group A) and those without scoliosis (Group B). The authors assessed the length of the syrinx, duration of morbidity, and clinical status before and after surgery based on the Japanese Orthopaedic Association (JOA) Scale.

There were 15 cases in Group A and 12 in Group B. The mean length of the syrinx was 12.8 vertebral bodies (VBs) in Group A and 7.2 VBs in Group B. The mean duration of morbidity was 14.2 years in Group A and 6.8 years in Group B. The mean preoperative JOA score was 10.1 in Group A and 14.4 in Group B, whereas the mean postoperative JOA scores were 11.9 and 15.8, respectively. There were significant differences between Groups A and B in length of the syrinx, duration of morbidity, and pre- and postoperative JOA scores.

Conclusions

In patients with syringomyelia and scoliosis the syringes spanned a greater number of VBs, the duration of morbidity was greater, neurological dysfunction was more severe, and surgical results were poorer. Scoliosis could be a predicting factor of the prognosis in patients with syringomyelia and Chiari malformation Type I.

Restricted access

Sho Kobayashi, Yukihiro Matsuyama, Kenichi Shinomiya, Shigenori Kawabata, Muneharu Ando, Tsukasa Kanchiku, Takanori Saito, Masahito Takahashi, Zenya Ito, Akio Muramoto, Yasushi Fujiwara, Kazunobu Kida, Kei Yamada, Kanichiro Wada, Naoya Yamamoto, Kazuhiko Satomi, and Toshikazu Tani

Object

Although multimodal intraoperative spinal cord monitoring provides greater accuracy, transcranial electrical stimulation motor evoked potential (TcMEP) monitoring became the gold standard for intraoperative spinal cord monitoring. However, there is no definite alarm point for TcMEPs because a multicenter study is lacking. Thus, based on their experience with 48 true-positive cases (that is, a decrease in potentials followed by a new neurological motor deficit postoperatively) encountered between 2007 and 2009, the authors set a 70% decrease in amplitude as the alarm point for TcMEPs.

Methods

A total of 959 cases of spinal deformity, spinal cord tumor, and ossification of the posterior longitudinal ligament (OPLL) treated between 2010 and 2012 are included in this prospective multicenter study (18 institutions). These institutions are part of the Japanese Society for Spine Surgery and Related Research monitoring working group and the study group on spinal ligament ossification. The authors prospectively analyzed TcMEP variability and pre- and postoperative motor deficits. A 70% decrease in amplitude was designated as the alarm point.

Results

There were only 2 false-negative cases, which occurred during surgery for intramedullary spinal cord tumors. This new alarm criterion provided high sensitivity (95%) and specificity (91%) for intraoperative spinal cord monitoring and favorable accuracy, except in cases of intramedullary spinal cord tumor.

Conclusions

This study is the first prospective multicenter study to investigate the alarm point of TcMEPs. The authors recommend the designation of an alarm point of a 70% decrease in amplitude for routine spinal cord monitoring, particularly during surgery for spinal deformity, OPLL, and extramedullary spinal cord tumor.

Restricted access

Takaki Inoue, Satoshi Maki, Toshitaka Yoshii, Takeo Furuya, Satoru Egawa, Kenichiro Sakai, Kazuo Kusano, Yukihiro Nakagawa, Takashi Hirai, Kanichiro Wada, Keiichi Katsumi, Kengo Fujii, Atsushi Kimura, Narihito Nagoshi, Tsukasa Kanchiku, Yukitaka Nagamoto, Yasushi Oshima, Kei Ando, Masahiko Takahata, Kanji Mori, Hideaki Nakajima, Kazuma Murata, Shunji Matsunaga, Takashi Kaito, Kei Yamada, Sho Kobayashi, Satoshi Kato, Tetsuro Ohba, Satoshi Inami, Shunsuke Fujibayashi, Hiroyuki Katoh, Haruo Kanno, Shiro Imagama, Masao Koda, Yoshiharu Kawaguchi, Katsushi Takeshita, Morio Matsumoto, Seiji Ohtori, Masashi Yamazaki, Atsushi Okawa, and

OBJECTIVE

It is unclear whether anterior cervical decompression and fusion (ADF) or laminoplasty (LMP) results in better outcomes for patients with K-line–positive (+) cervical ossification of the posterior longitudinal ligament (OPLL). The purpose of the study is to compare surgical outcomes and complications of ADF versus LMP in patients with K-line (+) OPLL.

METHODS

The study included 478 patients enrolled in the Japanese Multicenter Research Organization for Ossification of the Spinal Ligament and who underwent surgical treatment for cervical OPLL. The patients who underwent anterior-posterior combined surgery or posterior decompression with instrumented fusion were excluded. The patients with a follow-up period of fewer than 2 years were also excluded, leaving 198 patients with K-line (+) OPLL. Propensity score matching was performed on 198 patients with K-line (+) OPLL who underwent ADF (44 patients) or LMP (154 patients), resulting in 39 pairs of patients based on the following predictors for surgical outcomes: age, preoperative Japanese Orthopaedic Association (JOA) score, C2–7 angle, and the occupying ratio of OPLL. Clinical outcomes were assessed 1 and 2 years after surgery using the recovery rate of the JOA score. Complications and reoperation rates were also investigated.

RESULTS

The mean recovery rate of the JOA score 1 year after surgery was 55.3% for patients who underwent ADF and 42.3% (p = 0.06) for patients who underwent LMP. Two years after surgery, the recovery rate was 53.4% for those who underwent ADF and 38.7% for LMP (p = 0.07). Although both surgical procedures yielded good results, the mean recovery rate of JOA scores tended to be higher in the ADF group. The incidence of surgical complications, however, was higher following ADF (33%) than LMP (15%; p = 0.06). The reoperation rate was also higher in the ADF group (15%) than in the LMP group (0%; p = 0.01).

CONCLUSIONS

Clinical outcomes were good for both ADF and LMP, indicating that ADF and LMP are appropriate procedures for patients with K-line (+) OPLL. Clinical outcomes of ADF 1 and 2 years after surgery tended to be better than LMP, but the analysis did not detect any significant difference in clinical outcomes between the groups. Conversely, patients who underwent ADF had a higher incidence of surgery-related complications. When considering indications for ADF or LMP, benefits and risks of the surgical procedures should be carefully weighed.