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Motoki Iwasaki, Yoshiharu Kawaguchi, Tomoatsu Kimura, and Kazuo Yonenobu

Object. The authors report the long-term (more than 10-year) results of cervical laminoplasty for ossification of the posterior longitudinal ligament (OPLL) of the cervical spine as well as the factors affecting long-term postoperative course.

Methods. The authors reviewed data obtained in 92 patients who underwent cervical laminoplasty between 1982 and 1990. Three patients were lost to follow up, 25 patients died within 10 years of surgery, and 64 patients were followed for more than 10 years. Results were assessed using the Japanese Orthopaedic Association (JOA) scoring system for cervical myelopathy. The recovery rate was calculated using the Hirabayashi method. The mean neurological recovery rate during the first 10 years after surgery was 64%, which declined to 60% at the last follow-up examination (mean follow up 12.2 years). Late neurological deterioration occurred in eight patients (14%) from 5 to 15 years after surgery. The most frequent causes of late deterioration were degenerative lumbar disease (three patients), thoracic myelopathy secondary to ossification of the ligamentum flavum (two patients), or postoperative progression of OPLL at the operated level (two patients). Postoperative progression of the ossified lesion was noted in 70% of the patients, but only two patients (3%) were found to have related neurological deterioration. Additional cervical surgery was required in one patient (2%) because of neurological deterioration secondary to progression of the ossified ligament. The authors performed a multivariate stepwise analysis, and found that factors related to better clinical results were younger age at operation and less severe preexisting myelopathy. Younger age at operation, as well as mixed and continuous types of OPLL, was highly predictive of progression of OPLL. Postoperative progression of kyphotic deformity was observed in 8% of the patients, although it did not cause neurological deterioration.

Conclusions. When the incidence of surgery-related complications and the strong possibility of postoperative growth of OPLL are taken into consideration, the authors recommend expansive and extensive laminoplasty for OPLL.

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Masaki Kurihara, Yoshiharu Tokunaga, Keisuke Tsutsumi, Tsutomu Kawaguchi, Kazuto Shigematsu, Masami Niwa, and Kazuo Mori

✓ Receptors for insulin-like growth factor I (IGF-I) and epidermal growth factor (EGF) were localized and characterized in eight samples of human meningioma (four fibrous, two meningothelial, and two angioblastic types), using quantitative autoradiographic techniques. Effects of both growth factors on deoxyribonucleic acid (DNA) synthesis in the cultured meningioma cells were examined. High numbers of specific binding sites for both IGF-I and EGF were homogeneously present in tissue sections derived from fibrous and meningothelial types of meningiomas, whereas binding sites for these growth factors were not detectable in adjacent leptomeninges. While relatively large numbers of IGF-I binding sites were located in the wall of the intratumoral vasculature, the number of binding sites in the stromal component was lower in angioblastic-type meningiomas, including a low number of EGF binding sites detected only in the stromal portion. Scatchard analysis revealed the presence of a single class of high-affinity binding sites for both IGF-I and EGF in the meningiomas examined (dissociation constant (Kd) = 0.6 to 2.9 nM, and the maximum number of binding sites (Bmax) = 16 to 80 fmol/mg for IGF-I; and Kd = 0.6 to 4.0 nM, Bmax = 3 to 39 fmol/mg for EGF). Both growth factors increased the synthesis of DNA, in a dose-dependent manner, as measured by 3H-thymidine incorporation. The combination of IGF-I and EGF synergistically stimulated the synthesis of DNA, and the effects seen with 10% fetal bovine serum could be reproduced at a concentration of 10−10 M. These observations can be interpreted to mean that both IGF-I and EGF may be involved in the growth modulation of meningiomas, possibly through paracrine or autocrine mechanisms.

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Masato Nakano, Norikazu Hirano, Hirokazu Ishihara, Yoshiharu Kawaguchi, and Kousou Matsuura

Object. The purpose of this study was to analyze the risk factors for leakage of calcium phosphate cement (CPC) after vertebroplasty for osteoporotic vertebral fractures and to determine whether the vertebral body (VB) leakage caused any changes in the therapeutic benefits.

Methods. Between August 2000 and April 2002, the authors performed 65 CPC-assisted vertebroplasty procedures in 55 patients with thoracic or lumbar osteoporotic vertebral fractures. Back and low-back pain were evaluated using the visual analog scale and the duration of analgesic medication requirement. Factors related to CPC leakage and the postoperative outcome were analyzed.

There was a small amount of VB CPC leakage in 23 cases. In 10 of 23 cases, leakage into the epidural space was found. Although VB CPC leakage was independently associated with high initial age, female sex, high bone mineral density (BMD), short injury—surgery interval, and injection via the unipedicular route in the logistic regression analysis, there was no factor associated with CPC leakage into the epidural space. Cement leakage into the epidural space reduced the immediate therapeutic effects on fracture-related pain (p = 0.0128). All patients in whom cement leaked into the epidural space had improved by the 2-week follow-up examination.

Conclusions. Advanced initial age, female sex, high BMD, a short interval from injury to surgery, and injection via the unipedicular route may increase the incidence of CPC leakage. Cement leakage into the epidural space attenuated only the immediate therapeutic effects of CPC-assisted vertebroplasty.

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Masato Nakano, Norikazu Hirano, Hirokazu Ishihara, Yoshiharu Kawaguchi, Hiroki Watanabe, and Kousou Matsuura

Object

Few studies have been conducted to compare vertebroplasty and conservative treatment for osteoporotic vertebral compression fractures (OVCFs). To investigate the effects of calcium phosphate cement (CPC)–based vertebroplasty on relief of pain and augmentation of the fractured vertebral body (VB), the authors compared the results of CPC-assisted vertebroplasty with those of conservative treatment alone.

Methods

Two groups of patients were examined: the vertebroplasty group (30 consecutive patients with primary OVCF) and the control group (30 patients matched for age, sex, interval from injury to treatment, and grade of the posterior wall defects of the fractured VB). Outcome measures included the visual analog scale (VAS) score of back pain and analgesic requirements, and the radiographically documented rate of the VB kyphosis.

The follow-up duration was more than 12 months (mean 17 months). The mean VAS score at 12 months after injury was 0.67 cm in the vertebroplasty group and 1.97 cm in the control group, and the mean improvement rates in the VAS scores were 91.6 and 73.6%, respectively (p < 0.0001). The mean duration of analgesic requirement was 8.3 days in the vertebroplasty group and 62.2 days in the control group (p = 0.0005). The mean kyphosis rate at 12 months after injury was 72.9% in the vertebroplasty group and 58% in the control group, and the mean recovery rate of kyphosis was + 8.4 and −21%, respectively (p < 0.0001).

Conclusions

The authors conclude that CPC-assisted vertebroplasty provides better clinical and radiological results than conservative treatment for primary OVCF.

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Masato Nakano, Norikazu Hirano, Kousou Matsuura, Hiroki Watanabe, Hideki Kitagawa, Hirokazu Ishihara, and Yoshiharu Kawaguchi

Object. Osteoporotic vertebral fractures occasionally lead to late-onset collapse, kyphosis, persistent back pain, and disability. The authors describe a series of patients in whom they performed percutaneous vertebroplasty by using calcium phosphate cement (CPC) to obtain early pain relief and improve the integrity of the osteoporotic vertebral body (VB).

Methods. Between August 2000 and February 2001, they performed 17 percutaneous transpedicular CPC-assisted vertebroplasty procedures in 16 patients who harbored thoracic or lumbar osteoporotic vertebral fractures. Following repositioning and curettage of the pathological soft tissues, CPC-assisted vertebroplasty was percutaneously performed in four patients with osteoporotic burst fracture and pseudarthrosis (Procedure A). In situ CPC-assisted vertebroplasty was performed in 12 patients with fresh vertebral compression fractures due to osteoporosis (Procedure B). Back pain and low-back pain were evaluated using a visual analog scale (VAS). The deformity index of the VB was measured on a lateral radiograph as the ratio of the VB's height (sum of measurements at anterior, middle, and posterior regions) to its longitudinal diameter. Based on VAS scores, pain was decreased in all patients immediately after surgery, and pain relief was maintained at the last follow up. The mean preoperative deformity index score of the VB was 1.43 in Procedure A and 1.67 in Procedure B; postoperatively scores improved to 1.59 and 1.93, respectively. At the 6-month follow-up examination, the mean deformity index score rebounded to 1.52 in Procedure A and 1.79 in Procedure B. Bone union was documented in all patients. Complications, such as a temporary respiratory insufficiency and a small amount of CPC leakage into the spinal canal, were observed in patients who underwent Procedure B.

Conclusions. Percutaneous transpedicular CPC-assisted vertebroplasty is a minimally invasive procedure that provides early relief of pain and prevents vertebral collapse and pseudarthrosis in patients with osteoporotic vertebral fracture.

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Yoshiharu Kawaguchi, Takeshi Oya, Yumiko Abe, Masahiko Kanamori, Hirokazu Ishihara, Taketoshi Yasuda, Shigeharu Nogami, Takeshi Hori, and Tomoatsu Kimura

Object. Spinal stenosis due to lumbar ossified lesions is a rare pathological entity. The authors retrospectively evaluated the clinical features and surgical results associated with cases involving lumbar ossified lesion—induced stenosis.

Methods. Data obtained in 20 surgically treated patients with lumbar hyperostotic spinal stenosis were included. To evaluate the background of the disease, body mass index and general complications were assessed. Whole-spine radiological examination was conducted. The presence of ossification of the posterior longitudinal ligament or ossification of the ligamentum flavum was evaluated. Surgical results were classified according to the Japanese Orthopaedic Association (JOA) scale. In the patients in whom neurological deterioration was observed during follow up, the causes of deterioration were reviewed. Seven patients (35%) were obese and six patients (30%) suffered diabetes mellitus. Twelve patients harbored coexisting cervical and/or thoracic ossified lesions. The overall mean JOA score improved from 10.2 to a peak of 22.5; at last follow-up examination the mean JOA score was 20.9. In female and older patients with a long history of preoperative symptoms, a low preoperative JOA score, and other spinal lesions, recovery tended to be poorer. Recovery was poor in one patient, and neurological deterioration due to coexisting ossified spinal lesions occurred in another patient during the follow-up period.

Conclusions. Because coexisting ossified lesions were frequently seen, whole-spine analysis is recommended. Early diagnosis and appropriate treatment are important to achieve a better surgical outcome.

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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.