Hiroshi Kuroki

Comparative study of MR myelography and conventional myelography in the diagnosis of lumbar spinal diseases.

The purpose of this study was to investigate the usefulness of magnetic resonance (MR) myelography by comparing it with conventional myelography. MR myelography was performed on 40 patients (24 men and 16 women; mean age, 44 years) with lumbar spinal diseases. MR myelography was imaged three-dimensionally by fast spin-echo technique with fat suppression and maximum intensity projection. We assessed both the ability to provide the images of nerve root sheaths and the similarity of the findings to conventional myelography. Satisfactory images of nerve root sheaths in the lumbar region were provided almost equally by MR and conventional myelography. The images obtained by MR myelography were similar in quality to those obtained by conventional myelography. When combined with some other conventional MR imaging techniques, this diagnostic technique of imaging lumbar spinal diseases is further enhanced.

Significance of hanging total spine x-ray to estimate the indicative correction angle by brace wearing in idiopathic scoliosis patients

BackgroundAlthough most idiopathic scoliosis patients subject to conservative treatment in daily clinical practice, there have been no ideal methods to evaluate the spinal flexibility for the patients who are scheduled the brace treatment. The purpose of this study was to investigate the value of hanging total spine x-ray to estimate the indicative correction angle by brace wearing in idiopathic scoliosis patients.MethodsOne hundred seventy-six consecutive patients with idiopathic scoliosis who were newly prescribed the Osaka Medical College (OMC) brace were studied. The study included 14 boys and 162 girls with a mean age of 13 years and 1 month. The type of curves consisted of 62 thoracic, 23 thoracolumbar, 22 lumbar, 42 double major, 14 double thoracic, and 13 triple curve pattern. We compared the Cobb angles on initial brace wearing (BA) and in hanging position (HA). Of those, 108 patients who had main thoracic curves were selected and evaluated the corrective ability of OMC brace. These subjects were divided into three groups according to the relation between BA and HA (BA < HA group, BA = HA group, and BA > HA group), and then, maturity was compared among them.ResultsThe average Cobb angle in upright position (UA) of all cases was 31.0 ± 7.8°. The average BA and HA of all cases were 20.3 ± 9.5° and 21.1 ± 8.4°, respectively. The average chronological age was lowest in BA < HA group. And also, maturity in BA < HA group was the lowest among each of them. The rate of BA < HA cases were decreased as the Risser stage of the patients were progressed.ConclusionsThe use of hanging total spine x-ray served as a useful tool to estimate the degree of correction possible curve within the OMC brace for main thoracic curve in idiopathic scoliosis. Maturity had some influence on the correlation between HA and BA. Namely, in immature patients, HA tended to be larger than BA. In contrast, in mature patients, HA had a tendency to be smaller than BA. With consideration for spinal flexibility based on maturity, in mature patients, larger BA than HA may be allowed. However, in immature patients, smaller BA than HA should be aimed.

A comparative study of chemonucleolysis with recombinant human cathepsin L and chymopapain. A radiologic, histologic, and immunohistochemical assessment.

STUDY DESIGN Investigation of the effects of recombinant human cathepsin L on intervertebral discs and comparison with the effects of chymopapain. OBJECTIVE To evaluate the effects of cathepsin L on intervertebral discs as an agent for chemonucleolysis. SUMMARY BACKGROUND DATA Cathepsin L is a typical cysteine proteinase that belongs to the papain superfamily. It plays a major role in intracellular proteolysis and is not believed to induce anaphylactic reactions. METHODS In vivo: Rabbit intervertebral discs were injected with recombinant human cathepsin L, its buffer solution, and chymopapain. After 1, 4, and 16 weeks the animals were killed, and radiologic and histologic examinations were performed. In vitro: The enzymatic actions of recombinant human cathepsin L and chymopapain on human intervertebral disc proteoglycans were examined immunohistochemically using antiproteoglycan antibodies. RESULTS In rabbit models, roentgenography showed that disc spaces treated with cathepsin L and chymopapain had become narrower 1 week after injection. Histologically, loss of safranin-O staining was observed in the anulus fibrosus of discs treated with cathepsin L. After 16 weeks, nucleus pulposus had regenerated with chondrocyte-like cells, and the safranin-O staining characteristics of the matrix also had recovered. In an immunohistochemical study, all components of the proteoglycan stained weakly after chymopapain digestion. After cathepsin L digestion, unsulfated chondroitin and core protein staining was weaker, but the chondroitin 6-sulfate staining was unaffected. CONCLUSIONS Cathepsin L seems to be an effective agent for chemonucleolysis. Its enzymatic action on proteoglycan appears to be different from that of chymopapain.

Segmental square spinal instrumentation for posterior lumbar spinal fixation.

The purpose of this study is to evaluate the clinical results of operations using a new spinal instrumentation for posterior fixation, called segmental square spinal (3-S) instrumentation. The 3-S instrument consists of two pairs of hooks to clasp the interarticular portion of the lamina bilaterally, two horizontal bars to connect the hooks on the right and left, and rods to connect the hooks side by side on the top and bottom. Twenty-seven patients who had degenerative lumbar disorders underwent operations with the 3-S instrument. Rigid fixation was obtained in all cases immediately after the operation. Bone union rates were 91% (21/23) with posterolateral fusion. The 3-S instrument seems to be suitable for spinal disorders in which anterior spinal fusion is not necessary, especially for degenerative spinal disorders.

Long Thoracic and Lumbar Spinal Stabilization with a Minimally Invasive Spine Surgery Technique

Objectives: The purpose of the current case presentation was to indicate the usefulness of long thoracic and lumbar (TL) spinal stabilization by percutaneous minimally invasive instrumentation. Materials and methods: From August 2012 to May 2013, we performed long TL spinal stabilization with VIPER 2 system (Depuy Spine, Inc., MA, US) by using a minimally invasive surgery (MIS) posterior approach in 4 patients. The first case was a 54 year old male who suffered from burst fracture of T12 (Frankel A) with brain contusion by a fall. The second case was a 68 year old male who developed incomplete paraplegia by metastatic renal cell carcinoma of T11 (Frankel C). The third case was a 79 year old male who affected Chance fracture of T12 (Frankel E) with an ankylosing spinal hyperostosis. And the fourth case was a 75 year old male who sustained pathological fracture of T8 (Frankel A) due to metastasis of prostatic carcinoma accompanied by an ankylosing spinal hyperostosis. The assessment included the clinical outcome of the patients and implant imaging evaluation. Results: Physical function was improved in all cases with quick pain relief. Mean operative time was 204 minutes. Mean estimated blood loss was 62.5 ml. In radiographic evaluation, spinal alignment was successfully maintained. One pedicle screw in case 3 cut out laterally in a pedicle-rib unit, but other pedicle screws in all cases were correctly inserted. No implant related complication was observed. And there were no conversions to open surgery. Discussion: In comparison with conventional open surgery, intraoperative blood loss, operative time, and postoperative pain were remarkably decreased in a MIS technique. Long TL spinal stabilization with a MIS technique is useful method for the patients who are desirable to avoid major surgical procedure.

Posterior occipito-axial fixation applied C2 laminar screws for pediatric atlantoaxial instability caused by Down syndrome: Report of 2 cases

Background Upper cervical spine instability is one of the most critical orthopedic problems in patients with Down syndrome. However, arthrodesis of the upper cervical spine in these patients can be very difficult to achieve and has a high complication rate because of mental retardation and accompanying various medical conditions of the vital organs. Even now, surgeries in such patients, especially pediatric cases, are challenging and the optimal operative procedure remains unsettled. The purpose of this study was to report 2 cases of pediatric atlantoaxial instability due to Down syndrome in which posterior occipito-axial fixation with C2 laminar screws was performed. Methods Case 1 was a girl aged 6 years 10 months who had atlantoaxial rotatory fixation with os odontoideum. Atlantoaxial rotatory fixation was incompletely reduced by halo traction, and it was not maintained without halo-ring and -vest fixation. Posterior occipito-axial fixation with bilateral C2 laminar screws was then performed. Case 2 was a boy aged 10 years 7 months who had atlantoaxial subluxation with os odontoideum. He also had incomplete quadriplegia, so he could neither walk nor have a meal by himself. Posterior occipito-axial fixation with right C2 pedicle and left C2 laminar screws was then carried out. Results In case 1 bone union was obtained at 3 months after surgery and the patients symptoms were resolved. In case 2 bone union was obtained at 3 months after surgery and the paralysis was improved. Conclusions/level of evidence In cases of atlantoaxial instability due to Down syndrome, symptomatic patients often present between ages 5 and 15 years and mental retardation interferes with postoperative cervical immobilization. C2 laminar screws can be safely applied for the pediatric axis and biomechanically accomplished rigid fixation. The C2 laminar screw is one of the most useful options to achieve stability of the pediatric atlantoaxial complex without the risk of vertebral artery injuries (level IV case series).

Two siblings with neuropathic scoliosis caused by Chiari malformation type I with syringomyelia

Chiari malformation type I (CMI) has been considered a sporadic condition without a heritable etiology; however, there have been a number of case reports identifying familial aggregation and clustering of CMI, suggesting a genetic basis [1]. We report two siblings with neuropathic scoliosis (NS) caused by CMI with syringomyelia. The patients and their families were informed that data from the cases would be submitted for publication and gave their consent.

Commentary on Special Issue- Minimally Invasive Spine Surgery

Copyright:

Posterolateral Lumbar Fusion — Biomechanical Study and Clinical Results

This paper discusses the biomechanics and long-term results of posterolateral (PL) lumber fusion for degenerative lumbar spinal diseases. In the biomechanical study, the geometry of the finite element model is based on the L4-5 motion segment. The disc degeneration model was simulated by changing the interbody material properties. The behavior of the PL fusion model and the effects of the anterior elements on PL lumber fusion were studied in compression, flexion, and extension. In the clinical study, 40 patients with a mean age of 39 years (19 to 63) were treated with PL fusion and the mean follow-up period was 14 years. Clinical evaluation was made by the Japanese Orthopaedic Association (J.O.A.) score. Fusion success was determined by X-ray radiographs. Stress distribution results indicate that there were high stresses in the upper part of the grafted bone for PL fusion. The axial displacement of the L4 vertebral body and the stress of the grafted bone for PL fusion increased in the disc degeneration model. In flexion, the extension load stress concentrated on the L4 side of PL fusion model between transverse processes. Clinically, the J.O.A. score improved by 24 points postoperatively. Radiographically, the success rate of the fusion was 93%. The long-term results were so good that this technique can be recommended. It is suggested that the instability including the degree of disc degeneration is one of the important factors in PL lumbar fusion.