Long-Term Results of Posterior Vertebral Column Resection for Severe Thoracolumbar Kyphosis with Achondroplastic Patients: A Case Series.

Background and Objectives: Thoracolumbar kyphosis is one of the most frequent skeletal manifestations in patients with achondroplasia. Few papers have been published on the surgical treatment of this condition, especially in skeletally mature patients. With this study, we presented a retrospective case series of long-term surgical results for achondroplastic patients with severe thoracolumbar kyphosis. This study was conducted to evaluate the outcome of surgical treatment for thoracolumbar kyphosis in patients associated with achondroplasia presenting with paraparesis. Materials and Methods: Three patients with achondroplasia who developed neurologic deficits due to severe thoracolumbar kyphosis and underwent surgical treatment were evaluated (mean age 22.3 years; mean follow-up 9.3 years). All patients were treated with posterior vertebral column resection (p-VCR) of hypoplastic apical vertebrae with a cage and segmental instrumentation. Neurologic outcomes (JOA scores), correction of kyphosis, and operative complications were assessed. Results: All patients had back pain, neurological deficits, and urinary disturbance before surgery. The average preoperative JOA score was 8.3/11 points, which was improved to 10.7/11 points at the final follow-up (mean recovery rate 83%). All patients obtained neurologic improvement after surgery. The mean preoperative kyphotic angle was 117° (range 103°-126°). The postoperative angles averaged 37° (range 14°-57°), resulting in a mean correction rate of 67%. All patients had postoperative complications such as rod breakage and/or surgical site infection. Conclusions: The long-term results of p-VCR were acceptable for treating thoracolumbar kyphosis in patients with achondroplasia. To perform this p-VCR safely, spinal navigation and neuromonitoring are inevitable when resecting non anatomical fused vertebrae and ensuring correct pedicle screw insertion. However, surgical complications such as rod breakage and surgical site infection may occur at a high rate, making informed consent very important when surgery is indicated.

Effectiveness of using low rate fluoroscopy to reduce an examiner's radiation dose during lumbar nerve root block.

BACKGROUND: Long-term exposure to radiation can lead to gene mutations and increase the risk of cancer. Low rate fluoroscopy has the potential to reduce the radiation exposure for both the examiner and the patient during various fluoroscopic procedures. The purpose of this study was to evaluate the impact of low rate fluoroscopy on reducing an examiner's radiation dose during nerve root block. METHODS: A total of 101 lumbar nerve root block examinations were performed at our institute during a 6-month period. During the first 3 months, low rate fluoroscopy was performed at 7.5 frames/s (FPS) in 54 examinations, while 47 were performed at 15 FPS during the last 3 months. The examiner wore a torso protector, a neck protector, radiation protection gloves, and radiation protection glasses. Optically stimulated luminescence (OSL) dosimeter badges were placed on both the inside and the outside of each protector. The dosimeters were exchanged every month. Radiation doses (mSv) were measured as the integrated radiation quantity every month from the OSL dosimeters. The effective and equivalent doses for the hands, skin, and eyes were investigated. RESULTS: The mean monthly equivalent doses were significantly lower both inside and outside the hand protector for the 7.5 FPS versus 15 FPS (inside; P = 0.021, outside; P = 0.024). There were no significant differences between the two groups for the mean monthly calculated effective dose for each protector's condition. CONCLUSIONS: Radiation exposure was significantly reduced for the skin on the examiner's hand when using low rate fluoroscopy at 7.5 FPS, with no noticeable decrease in image quality or prolonged fluoroscopy time.

Collagen-Binding Hepatocyte Growth Factor (HGF) alone or with a Gelatin- furfurylamine Hydrogel Enhances Functional Recovery in Mice after Spinal Cord Injury.

The treatment of spinal cord injury (SCI) is currently a significant challenge. Hepatocyte growth factor (HGF) is a multipotent neurotrophic and neuroregenerative factor that can be beneficial for the treatment of SCI. However, immobilized HGF targeted to extracellular matrix may be more effective than diffusible, unmodified HGF. In this study, we evaluated the neurorestorative effects of an engineered HGF with a collagen biding domain (CBD-HGF). CBD-HGF remained in the spinal cord for 7 days after a single administration, while unmodified HGF was barely seen at 1 day. When a gelatin-furfurylamine (FA) hydrogel was applied on damaged spinal cord as a scaffold, CBD-HGF was retained in gelatin-FA hydrogel for 7 days, whereas HGF had faded by 1 day. A single administration of CBD-HGF enhanced recovery from spinal cord compression injury compared with HGF, as determined by motor recovery, and electrophysiological and immunohistochemical analyses. CBD-HGF alone failed to improve recovery from a complete transection injury, however CBD-HGF combined with gelatin-FA hydrogel promoted endogenous repair and recovery more effectively than HGF with hydrogel. These results suggest that engineered CBD-HGF has superior therapeutic effects than naïve HGF. CBD-HGF combined with hydrogel scaffold may be promising for the treatment of serious SCI.

Neurological Recovery after Posterior Spinal Surgery in Patients with Metastatic Epidural Spinal Cord Compression.

Metastatic epidural spinal cord compression (MESCC) is a common complication in patients with a malignant tumor, but it is difficult to decide the proper time to perform the necessary surgery. Here we analyzed the prognostic factors for postoperative walking ability. We retrospectively reviewed the cases of 112 MESCC patients treated surgically at our institute and divided them into ambulatory (n＝ 88) and non-ambulatory (n＝24) groups based on their American Spinal Injury Association (ASIA) Impairment Scale grades at the final follow-up. We also classified the patients preoperatively using the revised Tokuhashi score. We assessed the correlation between preoperative or intraoperative factors and postoperative walking ability in both groups. Of the 10 patients classified preoperatively as grade A or B, 2 (20% ) were ambulatory at the final follow-up. Of the 102 patients classified preoperatively as grade C, D or E, 86 (84% ) were ambulatory at the final follow-up (p＜0.001). There were no significant differences between the groups in the average total Tokuhashi score. Our analysis revealed that the severity of paralysis significantly affects neurological recovery in patients with MESCC. Patients with MESCC should receive surgery before the preoperative ASIA Impairment Scale grade falls below grade C.

A novel, visible light-induced, rapidly cross-linkable gelatin scaffold for osteochondral tissue engineering.

Osteochondral injuries remain difficult to repair. We developed a novel photo-cross-linkable furfurylamine-conjugated gelatin (gelatin-FA). Gelatin-FA was rapidly cross-linked by visible light with Rose Bengal, a light sensitizer, and was kept gelled for 3 weeks submerged in saline at 37°C. When bone marrow-derived stromal cells (BMSCs) were suspended in gelatin-FA with 0.05% Rose Bengal, approximately 87% of the cells were viable in the hydrogel at 24 h after photo-cross-linking, and the chondrogenic differentiation of BMSCs was maintained for up to 3 weeks. BMP4 fusion protein with a collagen binding domain (CBD) was retained in the hydrogels at higher levels than unmodified BMP4. Gelatin-FA was subsequently employed as a scaffold for BMSCs and CBD-BMP4 in a rabbit osteochondral defect model. In both cases, the defect was repaired with articular cartilage-like tissue and regenerated subchondral bone. This novel, photo-cross-linkable gelatin appears to be a promising scaffold for the treatment of osteochondral injury.

Does laminoplasty really improve neurological status in patients with cervical spinal cord injury without bone and disc injury? A prospective study about neurological recovery and early complications.

PURPOSE: Cervical spinal cord injury without bone and disc injury in patients with spinal cord compression is a fairly common problem in Japan. Because elderly Japanese population tend to have cervical spinal canal stenosis. However, there has been no consensus in the treatment of these patients. We conducted a prospective study to evaluate treatment outcomes and complications of these patients. METHODS: Twenty-five patients had been enrolled in this study. Patients who had paralysis of ASIA impairment scale (AIS) A, B or C were included. With each new patient, we alternated whether he/she received surgical treatment (group S) or conservative treatment (group C). Eleven patients were assigned to each group. We compared the two groups' courses of treatment and complications by evaluating their neurological symptoms using the AIS and ASIA motor score (MS) documenting them at the time of injury and 3 months later. RESULTS: The majority of clinical paralysis was found at the C3/4 level for both the groups. According to complications, there were seven urinary tract infections and four pneumonias in group S and one urinary tract infection and three pneumonias in group C. Both groups had an average MS of 42 at the time of injury. Three months later, the average MSs were 59 points in group S and 65 points in group C. CONCLUSIONS: In the present study, we found no significant difference in paralysis improvement between surgical and conservative treatment, although we observed a higher frequency of complications with surgery.

Enhanced in vivo osteogenesis by nanocarrier-fused bone morphogenetic protein-4.

PURPOSE: Bone defects and nonunions are major clinical skeletal problems. Growth factors are commonly used to promote bone regeneration; however, the clinical impact is limited because the factors do not last long at a given site. The introduction of tissue engineering aimed to deter the diffusion of these factors is a promising therapeutic strategy. The purpose of the present study was to evaluate the in vivo osteogenic capability of an engineered bone morphogenetic protein-4 (BMP4) fusion protein. METHODS: BMP4 was fused with a nanosized carrier, collagen-binding domain (CBD), derived from fibronectin. The stability of the CBD-BMP4 fusion protein was examined in vitro and in vivo. Osteogenic effects of CBD-BMP4 were evaluated by computer tomography after intramedullary injection without a collagen-sponge scaffold. Recombinant BMP-4, CBD, or vehicle were used as controls. Expressions of bone-related genes and growth factors were compared among the groups. Osteogenesis induced by CBD-BMP4, BMP4, and CBD was also assessed in a bone-defect model. RESULTS: In vitro, CBD-BMP4 was retained in a collagen gel for at least 7 days while BMP4 alone was released within 3 hours. In vivo, CBD-BMP4 remained at the given site for at least 2 weeks, both with or without a collagen-sponge scaffold, while BMP4 disappeared from the site within 3 days after injection. CBD-BMP4 induced better bone formation than BMP4 did alone, CBD alone, and vehicle after the intramedullary injection into the mouse femur. Bone-related genes and growth factors were expressed at higher levels in CBD-BMP4-treated mice than in all other groups, including BMP4-treated mice. Finally, CBD-BMP4 potentiated more bone formation than did controls, including BMP4 alone, when applied to cranial bone defects without a collagen scaffold. CONCLUSION: Altogether, nanocarrier-CBD enhanced the retention of BMP4 in the bone, thereby promoting augmented osteogenic responses in the absence of a scaffold. These results suggest that CBD-BMP4 may be clinically useful in facilitating bone formation.

Recovery of motor function in patients with subaxial cervical spine injury relevant to the fracture pattern.

In this study, we studied the relationship between fracture patterns and motor function recovery in 70 consecutive patients with cervical spinal cord injury. Fractures were categorized into 6 fracture types and subdivided into stages according to the Allen-Ferguson classification system:compressive flexion (CF), distractive flexion (DF), compressive extension (CE), distractive extension (DE), vertical compression (VC) and lateral flexion (LF). Paralysis was evaluated using the American Spinal Injury Association (ASIA) impairment scale at the time of injury and 3 months afterwards. The residual rate of complete motor palsy (ASIA grade A or B) at the final examination was higher in those patients with DE fractures than those with CF, DF or CE. The final outcomes were as follows. Of the 14 patients who were classified with CF fractures, residual palsy was frequently seen in patients who had stage 5 injury. Of the 27 patients with DF fractures, residual palsy occurred in about half of the patients who had stage 4 or 5 injury. Of the 18 patients with CE fractures, residual palsy occurred in half of the patients with stage 3 injury or higher. Finally, of the 7 patients with DE fractures, the rate of residual palsy was high even for the stage 1 and 2 cases;indeed, all DE patients who had complete motor palsy at the first examination had residual palsy at the final examination. Accordingly, we conclude that motor recovery may be related to fracture pattern.

Motion Induced Artifact Mimicking Cervical Dens Fracture on the CT Scan: A Case Report.

The diagnostic performance of helical computed tomography (CT) is excellent. However, some artifacts have been reported, such as motion, beam hardening and scatter artifacts. We herein report a case of motion-induced artifact mimicking cervical dens fracture. A 60-year-old man was involved in a motorcycle accident that resulted in cervical spinal cord injury and quadri plegia. Reconstructed CT images of the cervical spine showed a dens fracture. We assessed axial CT in detail, and motion artifact was detected.

Upper lumbar pedicle screw insertion using three-dimensional fluoroscopy navigation: assessment of clinical accuracy.

We used a navigation system to insert 128 pedicle screws into 69 vertebrae (L1 to L3) of 49 consecutive patients. We assessed the pedicle isthmic width and the permission angle for pedicle screw insertion. The permission angle is the angle defined by the greatest medial and lateral trajectories allowable when placing the screw through the center of the pedicle. The rate of narrow-width pedicles (isthmic width less than 5 mm) was 5 of 60 pedicles (8%) at L1, 4 of 60 pedicles (7%) at L2, and none (0%) at L3, L4 and L5. The rate of narrow-angle pedicles (a permission angle less than 15 degrees) was 21 of 60 pedicles (35%) at L1, 7 of 60 (12%) at L2, 3 of 60 (5%) at L3, and none (0%) at L4 and L5. Of 128 pedicle screws inserted into 69 vertebrae from L1 to L3, 125 (97.7%) were classified as Grade 1 (no pedicle perforation). In general, the upper lumbar vertebrae have more narrow-width and -angle pedicles. However, we could reduce the rate of pedicle screw misplacement in upper lumbar vertebra using a three-dimensional fluoroscopy and navigation system.

Early diagnosis and treatment may prevent the development of complications in an adult patient with glycogen storage disease type Ia.

Type Iota(a) glycogen storage disease (GSD Iota(a)) is caused by the deficiency of glucose-6-phosphatase activity, which results in metabolic disorder and organ failure, including renal failure. GSD Iota(a) patients are generally diagnosed at a median age of 6 months. However, we report a 20-year-old Japanese female with newly diagnosed GSD Iota(a) . The renal disorder of GSD Iota(a) is considered to be produced by glomerular hyperfiltration, TGF-beta expression which is induced by renin-angiotensin-aldosterone system (RAS) and uric acid, and the increase in both small dense LDL and modified LDL which is characteristic of GSD Iota(a) as well as hypertriglyceridemia. With the administration of intensive therapies, including angiotensin type 1-receptor blocker and some lipid lowering drugs, along with traditional dietary therapy, daily proteinuria of the patient improved from 2.1 g to 0.78 g. Although the patients of GSD Iota(a) should receive an early and accurate diagnosis and effective therapies before the age of 1 year, the combination of traditional dietary therapies and intensive therapies may have therapeutic potential for the complications of adult patients. In this report, we describe the management of renal disease and the characteristic features of this metabolic disorder.

Clinical accuracy of three-dimensional fluoroscopy (IsoC-3D)-assisted upper thoracic pedicle screw insertion.

Correct screw placement is especially difficult in the upper thoracic vertebrae. At the cervicothoracic junction (C7-T2), problems can arise because of the narrowness of the pedicle and the difficulty of using a lateral image intensifier there. Other upper thoracic vertebrae (T3-6) pose a problem for screw insertion also because of the narrower pedicle. We inserted 154 pedicle screws into 78 vertebrae (C7 to T6) in 38 patients. Screws were placed using intraoperative data acquisition by an isocentric C-arm fluoroscope (Siremobile Iso-C3D) and computer navigation. Out of 90 pedicle screws inserted into 45 vertebrae between C7 and T2, 87 of the 90 (96.7%) screws were classified as grade 1 (no perforation). Of 64 pedicle screws inserted into 33 vertebrae between T3 and T6, 61 of 64 (95.3%) screws were classified as grade 1. In this study, we reduced pedicle screw misplacement at the level of the C7 and upper thoracic (T1-6) vertebrae using the three-dimensional fluoroscopy navigation system.

Vertebral rotation during pedicle screw insertion in patients with cervical injury.

BACKGROUND: Cervical pedicle screws, when misplaced, tend to perforate laterally. One of the reasons for lateral perforation is vertebral rotation during screw insertion. However, actual vertebral rotation during pedicle screw insertion is unknown. In this study, we measured vertebral rotation during pedicle screw insertion in patients with cervical injury. METHODS: We inserted 76 pedicle screws into 38 vertebrae (C2 to C7) in 17 patients. All patients had some type of cervical injury. Screws were placed using intraoperative acquisition of data acquired with the isocentric C-arm fluoroscope (Iso-C3D) and computer navigation. We made screw holes using an image-guided awl, and we took images of cervical vertebrae in the neutral and rotational positions using navigation. Images of 76 insertions and rotational positions were taken while each cervical vertebra was under maximum stress at the time we were making the pedicle hole by awl. RESULTS: Average cervical vertebra rotation was 10.6 degrees (range 6 to 17) at C2, 9.1 degrees (5 to 13) at C3, 7.8 degrees (6 to 9) at C4, 6.7 degrees (4 to 11) at C5, 4.9 degrees (2 to 8) at C6, and 2.8 degrees (0 to 4) at C7. Vertebrae in the upper and middle cervical spine rotated more than the lower cervical spine vertebrae. Of the 76 pedicle screws inserted into vertebrae between C2 and C7, 74 screws (97.4%) were classified as grade 1 (no pedicle perforation). CONCLUSIONS: In this study, upper and middle cervical vertebrae in patients with neck injuries rotated more than the lower vertebrae. We should be especially careful of cervical rotation during screw insertion from C2 to C6, so as to prevent vertebral artery injury.