Remodeling of Lumbar Spinal Osteoid Osteoma Resected With Microscopic Surgery in a 15-Year-Old Basketball Player: A Case Report.

This case report focuses on a 15-year-old competitive-level high school basketball player who experienced chronic low back pain. Diagnostic imaging revealed osteoid osteoma in the L5 posterior element, causing osteosclerotic deformity of the left lamina and more inferior facet. To return him to the condition of sports activity, less invasive surgery of microscopic tumor resection with autologous bone grafting was planned instead of CT-guided ablation, which can cause thermal injury to nearby tissues. This procedure could preserve spinal structures, including the facet, pedicle, and paravertebral muscles. The day after surgery, the patient experienced a complete resolution of lower back pain. He gradually resumed light exercise two months postoperatively. Three-month follow-up CT imaging revealed bone remodeling at the resection site, to return to complete basketball activities. Over five years, no tumor recurrence or symptoms were observed, and he maintained his competitive activity level.

Traction Radiculopathy After Surgery for Lumbar Spinal Metastasis: A Case Report.

Treatment of spinal metastasis has attracted much attention globally, especially in Japan, with the advancement of cancer therapy. Among the metastases, those from breast and prostate cancers may be more important than others considering the high incidence of bone metastasis and the long-term prognosis. This condition often results in surgical procedures of spinal metastases to improve cancer patients' quality of life (QOL). In the present case, a patient with lumbar metastasis of breast cancer presented with right L5 nerve palsy after palliative laminectomy surgery with posterior fusion. The nerve palsy had improved after additional bone resection around the right L5 root. The mechanism of this postoperative leg paralysis was subclinical nerve root damage due to the narrowing of the intervertebral foramen caused by the tumor protrusion like lumber disc hernia and the stretching of the nerve roots caused by the posterior shift of the dural tube. When performing decompression and fixation of a metastatic spine showing a herniated tumor formed by a tumor protruding posteriorly into the intervertebral foraminal space, sufficient tumor mass debulking should be considered to avoid postoperative intervertebral foraminal stenosis.

Cervical Implant Allergy With Chronic Neck Pain: A Case Report.

A 57-year-old woman underwent cervical implant surgery for a dislocated cervical spine fracture, and she complained of continuous intractable neck pain after surgery. Eight years later, she developed a plantar skin rash, subsequently diagnosed as a metal allergy, and metal dentures were replaced with ceramic ones. The skin rash, however, persisted for four more years after that and was eventually treated with cervical implant removal. Subsequently, her skin rash and her neck pain improved simultaneously. This synchronous improvement strongly suggested that the neck pain could have been caused by a cervical implant allergy. We discuss a case of posterior cervical implant allergy that presented with neck pain and plantar skin rash years after surgery.

Augmented Reality Device for Preoperative Marking of Spine Surgery Can Improve the Accuracy of Level Identification.

Introduction: Wrong-site spine surgery is an incident that could result in possible severe complications. In this present spinal surgery, the accurate spinal level is confirmed via preoperative or intraoperative radiographic marking. However, the location of radiographic marking has been determined from the manual palpation on the landmarks of the body surface. As a result, severe spine deformity can make it hard to identify the spinal level by manual palpation, thus leading to misidentification of the spinal level.Recently, the use of mixed reality in spine surgery is gradually increasing. In this study, we will demonstrate a head-mounted display (HMD) device that can project a hologram (3D image) of the patient's bone onto the actual patient's body to improve the accuracy of level identification for spine surgery. Technical Note: 3D CT images are created preoperatively, and the bone's STL data (3D data) are generated with the workstation. The created STL data are downloaded to the augmented reality software Holoeyes, installed on the HMD. Through this device, surgeons can view the hologram (3D image) of a patient's bone overlaying on an actual patient's body.We temporally estimated the spinous process level only by manual palpation without an HMD. Then, we estimated the spinous process level again after matching this hologram to a real bone with an HMD. The accuracy of the level identification with an HMD and without an HMD was examined by radiographic marking in order to evaluate the misidentification rate of the level. Without an HMD, the misidentification rate of the level was at 26.5%, while with it, the rate was reduced to 14.3%. Conclusions: On preoperative marking, an HMD-projecting bone image onto a patient's body could allow us to estimate the spinal level more accurately. Identification of the spinal level using mixed reality is effective in preventing wrong-site spine surgery.

A Novel Technique of Mixed Reality Systems in the Treatment of Spinal Cord Tumors.

Several reports have compared spinal cord tumor removal techniques but none have clearly described the appropriate site and level of indication for laminectomy or laminoplasty. The approach method for tumor removal depends on the type and localization of the tumor and the surgeon's skill. Therefore, a system that can suggest various surgical techniques is useful for spinal cord tumor surgery. The mixed reality system introduced in this paper is an excellent system that can suggest various surgical procedures. Using this system for spinal cord tumor removal, we made the surgery less invasive; therefore, we introduced this system and demonstrated its usefulness. Stereoscopic data of the patients with spinal cord tumors were obtained from preoperative myelogram-CT data. Stereoscopic laminectomy models including tumors were created using Blender, a free three-dimensional (3D) image editing software. We observed these data as 3D object images using a head-mounted display (HMD). This HMD is commercially available and relatively inexpensive. The surgical procedure is determined by considering those 3D images, radiological diagnosis, and the skill of surgeons. Intraoperative confirmation of the laminectomy site could be performed using the HMD. The 3D visualization of pathological conditions resulted in correct preoperative surgical planning and less invasive surgery in all five cases. Stereoscopic images using HMDs allow us a more intuitive understanding of the positional relationship between the tumor and spinal structure. These 3D object images can bring us more accurate preoperative planning and proper determination of surgical methods.

The Utility of Augmented Reality in Spinal Decompression Surgery Using CT/MRI Fusion Image.

In spine surgery, instrumentation surgery using augmented reality (AR) and navigation systems have become widespread, while decompression surgery using those applications is not so common. However, we sometimes encounter intraoperative problems such as excessive blood loss or bony resection in decompression surgery. Therefore, a practical navigation system is needed for safer spinal decompression surgery. Furthermore, the cost of AR and navigation systems has been expensive. In this study, we report the utility of applying the AR system of the head-mounted display (HMD) at a lower cost to identify the osteotomy area of laminectomy for spinal decompression surgery. 3D CT/MRI fusion images are created preoperatively to generate 3D data consisting of the nerve elements, a dural tube and nerve roots, and the bony elements of the spine. Then, we made the 3D data of the bone after decompression by 3D editing free software. Uploading the created 3D data of both 3D CT/MRI fusion and preoperative planned laminectomy images to the AR software in the HMD, we could confirm the proper decompression area with the 3D images projected through the HMD. This system was useful for cervical and lumbar decompression for confirming the proper decompression area preoperatively. We could perform decompression surgery just designed with this system. This system is a preoperative planning system that allows 3D HMD visualization to keep track of surgical orientation. It does not allow preoperative verification so far. However, this system has various possible applications and is considered a promising system for the future.

Intracortical chondroma of the metacarpal bone: A case report.

BACKGROUND: Intracortical chondroma of the metacarpal bone which could be painful is an extremely rare condition and previously only one case has been reported. Due to the similar physical features and appearance on clinical imaging, it is difficult to differentiate between intracortical chondroma and osteoid osteoma. Therefore, pathological examination is usually required to establish a definite diagnosis, which is often carried out only after tumor removal. In this study, we describe a case of intracortical chondroma which developed in the metacarpal bone and demonstrate the utility of magnetic resonance imaging (MRI). CASE SUMMARY: We present a case of a 40-year-old man with intracortical chondroma of the metacarpal bone who was strongly suspected of having a tumor, and it was confirmed using contrast-enhanced MRI and successfully treated with curettage. MRI performed before tumor removal revealed signal intensity similar to that of the nidus of an osteoid osteoma. However, no abnormal intensity was observed in the bone or soft tissues surrounding the tumor. Such abnormalities on images would indicate the presence of soft-tissue inflammation, which are characteristics of osteoid osteoma. Furthermore, contrast-enhanced imaging revealed no increased enhancement of the areas surrounding the tumor. This is the first report to describe the contrast-enhanced MRI features of intracortical chondroma. This may serve as a guide for clinicians when intracortical chondroma is suspected. CONCLUSION: The contrast-enhanced MRI was useful for the differential diagnosis of intracortical chondroma.

A Well-Differentiated Liposarcoma in the Digit: A Case Report of the 5-Year Post-Surgical Follow-Up.

A liposarcoma is extremely rare in the digits. A 73-year-old woman was diagnosed with a lipoma in her middle finger 10 years ago. As this tumor increased in size and presented with imaging findings that were atypical of lipomas, careful marginal resection biopsy outside the pseudo-capsule was performed, and the tumor was diagnosed as a well-differentiated liposarcoma. At the 5-year follow-up, the patient showed no evidence of local recurrence or metastasis, with no loss of hand function. The findings from this case suggest that even for a lipomatous tumor in the digits, further imaging examination and resection biopsy should be considered if the tumor presents with features that are atypical of lipomas.

A Rare Case of an Osteoid Osteoma of the Rib Treated under Computed Tomography Guidance: A Case Report and Review of the Literature.

Osteoid osteoma (OO) usually occurs in the extremities of young adults. The tumor can arise in any part of the skeletal tissue; however, it is rarely found in the rib, with limited reports to date. In this report, we present a rare case of OO arising in the rib, which was successfully treated under computed tomography guidance with minimal invasiveness. At the final follow-up after 4 years, no local recurrence was observed.

Long-term results of Chiari pelvic osteotomy in patients with developmental dysplasia of the hip: indications for Chiari pelvic osteotomy according to disease stage and femoral head shape.

BACKGROUND: We evaluated the long-term results of Chiari pelvic osteotomy for developmental dysplasia of the hip (DDH) after follow-up of 10 years or more. The indications for Chiari osteotomy were assessed based on the results. METHODS: We evaluated 74 hips in 69 patients treated for DDH with Chiari osteotomy. The average postoperative follow-up period was 13 years. The mean age at the time of surgery was 32 years (range 6-64 years). The disease was classified into two stages based on joint space measurements on radiographs: an early stage (36 hips) in which the mean age at surgery was 21 years (range 6-48 years) and an advanced stage (38 hips) in which the mean age at surgery was 41 years (range 18-64 years). Femoral head shape was classified into two types based on measurements of the sphericity of the femoral head: spherical (33 hips) or flat (41 hips). Clinical manifestations were evaluated according to Japanese Orthopaedic Association (JOA) hip scores. The joint space was measured on radiographs as an index of the progression of osteoarthritis. We attempted to identify factors that affected the long-term results of Chiari osteotomy, especially in regard to disease stage and femoral head shape. RESULTS: The mean total JOA score was 72 preoperatively and 87 at final follow-up. It had improved in 66 hips and was worse in 7 hips. All of the worse cases were at the advanced stage at the time of surgery, and in 6 of the worse cases the femoral head was spherical. Hips with advanced DDH and a spherical femoral head had poor outcomes and exhibited joint space narrowing postoperatively. CONCLUSIONS: Early DDH is considered a good indication for Chiari pelvic osteotomy because of the good results at 10 years or more. Even with advanced DDH, a flat femoral head predicts a good surgical outcome, but patients with a spherical femoral head may experience early progression to osteoarthritis.

Type II collagen synthesis in the articular cartilage of a rabbit model of osteoarthritis: expression of type II collagen C-propeptide and mRNA especially during early-stage osteoarthritis.

BACKGROUND: The aim of this study was to observe time course changes in type II collagen synthesis in various regions of articular cartilage affected with osteoarthritis (OA) by examining the expression of type II collagen C-propeptide (pCOL II-C) and mRNA in a rabbit OA model. METHODS: Osteoarthritis was experimentally induced by partial lateral meniscectomy in the knees of Japanese white rabbits. The cartilage of the animals was then examined histologically over time. The degenerative area of articular cartilage was divided into three areas, according to the degree of degeneration. The ability to synthesize type II collagen was estimated by the immunohistological staining of pCOL II-C and the in situ hybridization of mRNA in type II collagen. RESULTS: The positive rate of pCOL II-C immunostaining in chondrocytes was highest in the central-degenerative region 1 week after surgery, and the highest rate in the para-degenerative region was observed 2 and 4 weeks after surgery. The percentage of pCOL II-C positive cells increased as the histological degeneration score increased to moderate degeneration and then decreased with further progression of the severity of cartilage degeneration. Examination by in situ hybridization revealed that the regions marked by strong pCOL II-C mRNA expression were similar to those indicated by the immunohistology results. CONCLUSIONS: These results suggest that the type II collagen-synthesizing potential of chondrocytes is highest in moderately degenerated areas of OA articular cartilage. Cartilage repair continues to be seen even as OA advances, although the reaction varies depending on the stage of OA.