Analysis of implants for metastatic bone tumors of the proximal femur: A retrospective study

AIM

To investigate the relationship between surgical techniques used in our hospital to treat metastatic bone tumors of the proximal femur and activity level and prognosis of patients and whether the location of the tumor is considered when selecting surgical techniques.

METHODS

We retrospectively reviewed 82 patients with metastatic bone tumors of the proximal femur who underwent intramedullary nail fixation (IMN), bipolar hip arthroplasty (BHP) or modular megaprosthesis (MMP) in our hospital from 2007 to 2020. We measured the distance from the center of femoral head to the proximal (x) and distal (y) end of the of tumor, using preoperative computed tomography images to determine the location of metastasis. We also measured revised Katagiri score at the time of fracture, postoperative ISOLS/MSTS (functional outcome) scores, and overall survival.

RESULTS

The value of x was significantly different among the three groups. The value of y showed a significant difference between the IMN and BHP groups and the BHP and MMP groups. The functional outcome score was significantly lower in the IMN group. The survival rate of the patient tended to be higher in the BHP and MMP groups than in the IMN group 1 year postoperatively.

CONCLUSION

IMN was favored when the distance from the center of femoral head to the proximal end of the tumor was ≥15 mm. In the case of prosthetic replacement, BHP was chosen if the distance from the center of femoral head to the distal end of the tumor was ≤70 mm. BHP and MMP were preferred over IMN functionally.

Partial Sacral Resection for the Treatment of Isolated Testicular Tumor Metastasis

We encountered an uncommon case of a non-seminomatous germ cell tumor with solitary bone metastasis at the initial presentation. A 30-year-old male patient with testicular cancer underwent an orchidectomy and was diagnosed with non-seminoma. Positron emission tomography-computed tomography detected an isolated metastatic lesion in the right sacral wing, which disappeared after a series of chemotherapy. En-bloc surgical resection was performed as curative local treatment, and the patient was able to perform his activities of daily living with no apparent recurrence. Therefore, this surgical method is considered safe and beneficial for the treatment of sacral wing lesions.

Effect of low body mass index on clinical recovery after fusion surgery for osteoporotic vertebral fracture: A retrospective, multicenter study of 237 cases

A retrospective multicenter study. Body mass index (BMI) is recognized as an important determinant of osteoporosis and spinal postoperative outcomes; however, the specific impact of BMI on surgery for osteoporotic vertebral fractures (OVFs) remains inconclusive. This retrospective multicenter study investigated the impact of BMI on clinical outcomes following fusion surgery for OVFs. 237 OVF patients (mean age, 74.3 years; 48 men and 189 women) with neurological symptoms who underwent spinal fusion were included in this study. Patients were grouped by World Health Organization BMI categories: low BMI (<18.5 kg/m2), normal BMI (≥18.5 and <25 kg/m2), and high BMI (≥25 kg/m2). Patients' backgrounds, surgical method, radiological findings, pain measurements, activities of daily living (ADL), and postoperative complications were compared after a mean follow-up period of 4 years. As results, the proportion of patients able to walk independently was significantly smaller in the low BMI group (75.0%) compared with the normal BMI group (89.9%; P = .01) and the high BMI group (94.3%; P = .04). Improvement in the visual analogue scale for leg pain was significantly less in the low BMI group than the high BMI group (26.7 vs 42.8 mm; P = .046). Radiological evaluation, the Frankel classification, and postoperative complications were not significantly different among all 3 groups. Improvement of pain intensity and ADL in the high BMI group was equivalent or non-significantly better for some outcome measures compared with the normal BMI group. Leg pain and independent walking ability after fusion surgery for patients with OVFs improved less in the low versus the high BMI group. Surgeons may want to carefully evaluate at risk low BMI patients before fusion surgery for OVF because poor clinical results may occur.

Cardiac Arrest Due to Pulmonary Embolism After Posterior Spinal Fusion in a Patient With Acute Paraplegia Caused by a Metastatic Spinal Tumor Associated With Congenital Antithrombin III Deficiency

Congenital antithrombin (AT) III deficiency has a high incidence of deep vein thrombosis and pulmonary embolism due to reduced anticoagulation. In this study, we report a case of a patient who experienced cardiac arrest due to pulmonary embolism after emergency posterior spinal fusion for acute paraplesia due to a metastatic spinal tumor associated with AT III deficiency. A 49-year-old man with a history of familial AT III deficiency visited our hospital due to difficulty in walking caused by a progressive paralysis of the lower limbs. Clinical examination revealed multiple bone metastases due to prostate cancer and spinal cord compression caused by a pathological fracture of the T1 vertebral body. He had low AT III activity levels and high D-dimer levels. The following day, he underwent posterior spinal decompression and fusion. However, he had pulmonary embolism with cardiac arrest three days after surgery. He recovered without sequelae after emergency thrombectomy following resuscitation. Patients with AT III deficiency who cannot walk due to a metastatic spinal tumor inevitably develop deep vein thrombosis and pulmonary embolism. To avoid lethal pulmonary embolism, preventing deep vein thrombosis should be prioritized before surgery, even in the presence of acute progressive paraplegia.

Doxorubicin Combined With Ifosfamide for Sarcoma Induces Muscle Atrophy and Sleep Disruption

BACKGROUND/AIM

There are no reports evaluating sleep disturbance and skeletal muscle loss in response to the treatment of soft tissue sarcoma (STS) with chemotherapy. This study investigated the effects of combined doxorubicin (DXR) and ifosfamide (IFM) on sleep and skeletal muscle.

PATIENTS AND METHODS

This retrospective cohort study included 14 patients with high-grade STS. Participants underwent five 7-day hospitalizations during which they received chemotherapy for 5 consecutive days. Sleep analysis and muscle-volume evaluation were investigated using a wearable device during hospitalization and by bioelectrical impedance analysis at each chemotherapy course.

RESULTS

Chemotherapy significantly impeded sleep, increased wake-time after sleep onset, and aggravated movement index during hospitalization. In long-term body composition assessment, chemotherapy induced muscle-mass loss and fat-mass gain.

CONCLUSION

Combination of DXR and IFM for STS induces skeletal muscle loss and sleep disruption.

The Thioredoxin Reductase Inhibitor Auranofin Suppresses Pulmonary Metastasis of Osteosarcoma, But Not Local Progression

BACKGROUND/AIM

Auranofin (AUR), a thioredoxin reductase (TXNRD) inhibitor, shows anticancer activity against several cancers. This study investigated the effects of AUR on the local progression and pulmonary metastasis of osteosarcoma (OS).

MATERIALS AND METHODS

Publicly available expression cohorts were analysed to study the relationship between TXNRD-2 expression and the survival of patients with OS. The murine OS cell line LM8 was stimulated with AUR. Cell viability, apoptosis-related protein levels, caspase activity, and wound healing were analysed. Tumor progression and pulmonary metastasis were investigated in C3H mice implanted with LM8 cells.

RESULTS

High-level expression of TXNRD-2 represented a negative prognostic factor for metastasis and overall survival in patients with OS. AUR induced apoptosis of OS cells via the oxidative stress-MAPK-Caspase 3 pathway, and suppressed the migration of OS cells. AUR inhibited the pulmonary metastasis of OS, but not local progression.

CONCLUSION

AUR represents a potential therapeutic drug for suppressing pulmonary metastasis of OS.

Poor Efficacy of Postoperative Radiotherapy in Infiltrative High-grade Soft Tissue Sarcomas

BACKGROUND/AIM

We aimed to investigate the effectiveness of postoperative radiotherapy (RT) on local recurrence-free survival (LRFS) in high-grade infiltrative soft tissue sarcomas (STSs) and determine its prognostic factors.

PATIENTS AND METHODS

This was a retrospective cohort study and included 132 patients with high-grade STSs. Patients were divided into two groups: Group RT (n=48) who underwent postoperative RT and Group No-RT (n=84) who underwent only surgery. We analysed 5-year LRFS and its prognostic factors between these groups. Furthermore, 5-year LRFS in infiltrative and non-infiltrative STSs were evaluated.

RESULTS

Five-year LRFS was not significantly different in Group RT (83.6%) and Group No-RT (79.6%) (p=0.698). Overall, significant prognostic factors influencing LRFS were age at diagnosis (p=0.02) and tumour growth pattern (p=0.04). Postoperative RT was less effective in the infiltrative than in non-infiltrative pattern of STSs.

CONCLUSION

Postoperative RT does not influence local recurrence outcomes in infiltrative STSs.

CDK4 overexpression is a predictive biomarker for resistance to conventional chemotherapy in patients with osteosarcoma

Osteosarcoma (OS) is the most common malignant bone tumor, and its sensitivity to preoperative chemotherapy is a significant prognostic factor. The present study aimed to identify potential genomic markers for the prediction of chemosensitivity in patients with OS using a genomic approach. A total of 50 pediatric and adolescent patients diagnosed with high‑grade OS were selected. Each pre‑therapeutic biopsy sample was subjected to comparative genomic hybridization array analysis and targeted exome sequencing. Although no recurrent gene mutation was observed in chemoresistant tumors, copy number analysis detected recurrent gain of chromosome 12q14.1, which was significantly more frequent (5/21; 24%) in the poor responder cohort than in the good responder cohort (0/29; 0%; P<0.01). Subsequent expression analysis revealed that CDK4 was the only gene in the 12q14.1 gained region with an expression level that was positively associated with copy number gains. In order to elucidate the effect of CDK4 on drug sensitivity, CDK4‑overexpressing OS cell lines were treated with cisplatin (CDDP); significant attenuation of CDDP sensitivity, demonstrated by increased cell viability and decreased expression of cleaved caspase‑9, was induced by enforced expression of CDK4. In addition, treatment with CDK4/6 inhibitor palbociclib in CDK4‑overexpressing U2OS cells facilitated apoptosis and a significant decrease in cell viability in a dose‑dependent manner. In conclusion, the results of the present study showed that higher expression and amplification of CDK4 in tumors is a predictive biomarker for resistance to conventional chemotherapy in patients with OS and that palbociclib is a promising drug for this therapeutically challenging cohort.

Effectiveness of Salvage Knee Rotationplasty on Sarcoma Around the Knee in Adolescents and Young Adults

BACKGROUND/AIM

This study aimed to investigate the effectiveness of knee rotationplasty (KRP) as salvage surgery for uncontrolled infection and implant failure of total knee arthroplasty (TKA) for sarcoma around the knee in adolescents and young adults (AYA).

PATIENTS AND METHODS

This retrospective cohort study included 33 patients who underwent KRP and were grouped based on the treatment received: initial surgery for sarcoma around the knee (n=18) or as salvage surgery (n=15). Musculoskeletal Tumor Society (MSTS) score, range of motion (ROM) and postoperative results were analyzed.

RESULTS

All 15 patients who underwent salvage KRP had TKA as an initial surgery. Although there were five infections in salvage KRP, which originated from the initial TKA, all cases were controllable, no implant failure occurred. MSTS score and ROM were deemed acceptable in both groups.

CONCLUSION

Salvage KRP is an effective option for uncontrolled complications of initial TKA for sarcoma around the knee.

Short- versus long-segment posterior spinal fusion with vertebroplasty for osteoporotic vertebral collapse with neurological impairment in thoracolumbar spine: a multicenter study

Background

Vertebroplasty with posterior spinal fusion (VP + PSF) is one of the most widely accepted surgical techniques for treating osteoporotic vertebral collapse (OVC). Nevertheless, the effect of the extent of fusion on surgical outcomes remains to be established. This study aimed to evaluate the surgical outcomes of short- versus long-segment VP + PSF for OVC with neurological impairment in thoracolumbar spine.

Methods

We retrospectively collected data from 133 patients (median age, 77 years; 42 men and 91 women) from 27 university hospitals and their affiliated hospitals. We divided patients into two groups: a short-segment fusion group (S group) with 2- or 3-segment fusion (87 patients) and a long-segment fusion group (L group) with 4- through 6-segment fusion (46 patients). Surgical invasion, clinical outcomes, local kyphosis angle (LKA), and complications were evaluated.

Results

No significant differences between the two groups were observed in terms of neurological recovery, pain scale scores, and complications. Surgical time was shorter and blood loss was less in the S group, whereas LKA at the final follow-up and correction loss were superior in the L group.

Conclusion

Although less invasiveness and validity of pain and neurological relief are secured by short-segment VP + PSF, surgeons should be cautious regarding correction loss.

Effect of bisphosphonates or teriparatide on mechanical complications after posterior instrumented fusion for osteoporotic vertebral fracture: a multi-center retrospective study

Background

The optimal treatment of osteoporosis after reconstruction surgery for osteoporotic vertebral fractures (OVF) remains unclear. In this multicentre retrospective study, we investigated the effects of typically used agents for osteoporosis, namely, bisphosphonates (BP) and teriparatide (TP), on surgical results in patients with osteoporotic vertebral fractures.

Methods

Retrospectively registered data were collected from 27 universities and affiliated hospitals in Japan. We compared the effects of BP vs TP on postoperative mechanical complication rates, implant-related reoperation rates, and clinical outcomes in patients who underwent posterior instrumented fusion for OVF. Data were analysed according to whether the osteoporosis was primary or glucocorticoid-induced.

Results

A total of 159 patients who underwent posterior instrumented fusion for OVF were included. The overall mechanical complication rate was significantly lower in the TP group than in the BP group (BP vs TP: 73.1% vs 58.2%, p = 0.045). The screw backout rate was significantly lower and the rates of new vertebral fractures and pseudoarthrosis tended to be lower in the TP group than in the BP group. However, there were no significant differences in lumbar functional scores and visual analogue scale pain scores or in implant-related reoperation rates between the two groups. The incidence of pseudoarthrosis was significantly higher in patients with glucocorticoid-induced osteoporosis (GIOP) than in those with primary osteoporosis; however, the pseudoarthrosis rate was reduced by using TP. The use of TP also tended to reduce the overall mechanical complication rate in both primary osteoporosis and GIOP.

Conclusions

The overall mechanical complication rate was lower in patients who received TP than in those who received a BP postoperatively, regardless of type of osteoporosis. The incidence of pseudoarthrosis was significantly higher in patients with GIOP, but the use of TP reduced the rate of pseudoarthrosis in GIOP patients. The use of TP was effective to reduce postoperative complications for OVF patients treated with posterior fusion.

Factors Linked to Prognosis in Patients with Leptomeningeal Metastasis Diagnosed by Spinal Magnetic Resonance Imaging

Introduction

Leptomeningeal metastasis (LM) is known to demonstrate a very poor prognosis. The purpose of this study was to evaluate the prognostic factors in LM cases diagnosed by spinal magnetic resonance imaging (MRI).

Methods

We retrospectively analyzed 19 patients with LM detected by spinal MRI between 2010 and 2017.

Results

The primary tumors were breast carcinoma (n = 7), lung carcinoma (n = 6), lymphoma (n = 3), colorectal carcinoma (n = 2), and gastric carcinoma (n = 1). Thirteen patients exhibited preceding brain metastasis, and 11 of these exhibited metastasis in the posterior fossa. Ten patients exhibited limb paralysis. Performance status at diagnosis was 0-1 in 6 patients, 2 in 9 patients, and 3-4 in 4 patients. Testing of cerebrospinal fluid revealed malignant cells in 9 patients.

On MRI, 11 patients demonstrated disseminated tumor lesions at the cervical cord level, 15 patients at the thoracic cord level, and 11 patients below the conus level. Eleven patients received radiation therapy, while intrathecal chemotherapy was performed in 9 patients.

Univariate analysis revealed cervical cord level lesions, intrathecal chemotherapy, paralysis, and performance status as prognostic factors. Multivariate analysis identified existence of a cervical cord lesion as associated with a poor prognosis (hazards ratio (HR) 3.46, 95% confidence interval (CI) 1.12-12.2), while administration of intrathecal chemotherapy was associated with a good prognosis (HR 0.15, 95% CI 0.026-0.67).

Conclusions

In LM patients, cervical cord level lesions are a negative factor for prognosis, and performance of intrathecal chemotherapy is a positive factor for prognosis.

The Surgical Outcomes of Spinal Fusion for Osteoporotic Vertebral Fractures in the Lower Lumbar Spine with a Neurological Deficit

Introduction

Osteoporotic vertebral fracture (OVF) is the most common osteoporotic fracture, and some patients require surgical intervention to improve their impaired activities of daily living with neurological deficits. However, many previous reports have focused on OVF around the thoracolumbar junction, and the surgical outcomes of lumbar OVF have not been thoroughly discussed. We aimed to investigate the surgical outcomes for lumbar OVF with a neurological deficit.

Methods

Patients who underwent fusion surgery for thoracolumbar OVF with a neurological deficit were enrolled at 28 institutions. Clinical information, comorbidities, perioperative complications, Japanese Orthopaedic Association scores, visual analog scale scores, and radiographic parameters were compared between patients with lower lumbar fracture (L3-5) and those with thoracolumbar junction fracture (T10-L2). Each patient with lower lumbar fracture (L group) was matched with to patients with thoracolumbar junction fracture (T group).

Results

A total 403 patients (89 males and 314 females, mean age: 73.8 ± 7.8 years, mean follow-up: 3.9 ± 1.7 years) were included in this study. Lower lumbar OVF was frequently found in patients with lower bone mineral density. After matching, mechanical failure was more frequent in the L group (L group: 64%, T group: 39%; p < 0.001). There was no difference between groups in the clinical and radiographical outcomes, although the rates of complication and revision surgery were still high in both groups.

Conclusions

The surgical intervention for OVF is effective in patients with myelopathy or radiculopathy regardless of the surgical level, although further study is required to improve clinical and radiographical outcomes.

Level of evidence

Level III

A novel unidirectional porous β-tricalcium phosphate grafting for vertebral fracture in the elderly: preliminary case series

Objective: To treat vertebral fractures with posterior wall injury in the elderly, vertebral bone grafting is generally performed through a posterior transpedicular approach, combined with pedicle screw fixation. An autologous bone is ideal to treat this disorder. However, harvesting autologous bones from the elderly with osteoporosis is limited by the amount and quality of available autologous bone. Thus, we developed a bone-grafting substitute. The newly developed unidirectional porous β-tricalcium phosphate, with a porosity of 57% (UDPTCP; Affinos^®, Kuraray Co., Ltd., Tokyo, Japan), is used in the bone-grafting procedure. This is the first report of UDPTCP used as an artificial bone graft in patients with an acute vertebral burst fracture.

Materials and Methods: UDPTCP (mean: 4.2 g) was implanted through the pedicle, and posterior instrumentation was achieved with pedicle screws in five elderly patients. Resorption of UDPTCP and substitution with the autologous bone were evaluated on computed tomography (CT) and plain X-ray performed immediately and at 3, 6, and 12 months after the operation.

Results: In case 1, the pedicle screws did not loosen, and UDPTCP was completely resorbed and replaced with the autologous bone at 3 postoperative months. In the other four cases, although the pedicle screws or the caudal part loosened because of osteoporosis, resorption of UDPTCP was observed at 3 postoperative months. At 6 postoperative months, progressive substitution with the autologous bone was confirmed, and at 12 postoperative months, formation of the good autologous bone was confirmed.

Conclusion: This preliminary case series demonstrated that the newly developed UDPTCP shows good clinical potential as a bone-graft substitute for acute vertebral burst fractures in the elderly, including patients with osteoporosis.

Complications after spinal fixation surgery for osteoporotic vertebral collapse with neurological deficits: Japan Association of Spine Surgeons with ambition multicenter study

BACKGROUND

There have been few reports on the incidence and risk factors of the complications after spinal fixation surgery for osteoporotic vertebral collapse (OVC) with neurological deficits. This study aimed to identify the incidence and risk factors of the complications after OVC surgery.

METHODS

In this retrospective multicenter study, a total of 403 patients (314 women and 89 men; mean age 73.8 years) who underwent spinal fixation surgery for OVC with neurological deficits between 2005 and 2014 were enrolled. Data on patient demographics were collected, including age, sex, body mass index, smoking, steroid use, medical comorbidities, and surgical procedures. All postoperative complications that occurred within 6 weeks were recorded. Patients were classified into two groups, namely, complication group and no complication group, and risk factors for postoperative complications were investigated by univariate and multivariate analyses.

RESULTS

Postoperative complications occurred in 57 patients (14.1%), and the most common complication was delirium (5.7%). In the univariate analysis, the complication group was found to be older (p = 0.039) and predominantly male (p = 0.049), with higher occurrence rate of liver disease (p = 0.001) and Parkinson's disease (p = 0.039) compared with the no-complication group. In the multivariate analysis, the significant independent risk factors were age (p = 0.021; odds ratio [OR] 1.051, 95% confidence interval [CI] 1.007-1.097), liver disease (p < 0.001; OR 8.993, 95% CI 2.882-28.065), and Parkinson's disease (p = 0.009; OR 3.636, 95% CI 1.378-9.599).

CONCLUSIONS

Complications after spinal fixation surgery for OVC with neurological deficits occurred in 14.1%. Age, liver disease, and Parkinson's disease were demonstrated to be independent risk factors for postoperative complications.

Surgical outcomes of spinal fusion for osteoporotic vertebral fracture in the thoracolumbar spine: Comprehensive evaluations of 5 typical surgical fusion techniques

BACKGROUND

A consensus on the optimal surgical procedure for thoracolumbar OVF has yet to be reached due to the previous relatively small number of case series. The study was conducted to investigate surgical outcomes for osteoporotic vertebral fracture (OVF) in the thoracolumbar spine.

METHODS

In total, 315 OVF patients (mean age, 74 years; 68 men and 247 women) with neurological symptoms who underwent spinal fusion with a minimum 2-year follow-up were included. The patients were divided into 5 groups by procedure: anterior spinal fusion alone (ASF group, n = 19), anterior/posterior combined fusion (APSF group, n = 27), posterior spinal fusion alone (PSF group, n = 40), PSF with 3-column osteotomy (3CO group, n = 92), and PSF with vertebroplasty (VP + PSF group, n = 137).

RESULTS

Mean operation time was longer in the APSF group (p < 0.05), and intraoperative blood loss was lower in the VP + PSF group (p < 0.05). The amount of local kyphosis correction was greater in the APSF and 3CO groups (p < 0.05). Clinical outcomes were approximately equivalent among all groups.

CONCLUSION

All 5 procedures resulted in acceptable neurological outcomes and functional improvement in walking ability. Moreover, they were similar with regard to complication rates, prevalence of mechanical failure related to the instrumentation, and subsequent vertebral fracture. Individual surgical techniques can be adapted to suit patient condition or severity of OVF.

Freeze-Dried Platelet-Rich Plasma Induces Osteoblast Proliferation via Platelet-Derived Growth Factor Receptor-Mediated Signal Transduction

Study Design

Controlled laboratory study.

Purpose

This study aimed to evaluate the in vitro pharmacological activity of growth factors (GFs) in freeze-dried platelet-rich plasma (FD-PRP) after storage for 4 weeks.

Overview of Literature

Freshly prepared PRP is a rich source of many GFs. We reported that FD-PRP stored for 8 weeks accelerated bone union in a rat posterolateral fusion model equally well as fresh-PRP. However, the pharmacological activity of FD-PRP after long-term storage has not been shown in vitro.

Methods

Immediately after preparation, as well as 4 weeks after freeze-dried storage, the platelet count was measured. Human osteoblasts were treated with fresh-PRP and FD-PRP, respectively. Western blotting was used to assess the phosphorylation of the platelet-derived growth factor (PDGF) receptor (PDGFR) and its downstream target, extracellular signal-regulated kinase (ERK). The proliferation rates of osteoblasts were investigated by immunocytochemistry and MTT cell viability assays. Furthermore, we used western blotting to evaluate the effect of PDGFR knockdown on the phosphorylation of ERK stimulated with fresh-PRP and FD-PRP.

Results

Platelet counts in both the fresh-PRP and FD-PRP samples were approximately 10-fold higher than in peripheral blood samples. The phosphorylation and activation of the PDGFR and ERK were evenly induced by fresh-PRP and FD-PRP stimulation. Both freshPRP and FD-PRP significantly induced osteoblast proliferation in MTT cell viability assays. Furthermore, osteoblast PDGFR knockdown attenuated the downstream ERK activation by fresh PRP and FD-PRP.

Conclusions

We demonstrated the pharmacological activity of PDGF in FD-PRP in vitro after 4 weeks of storage.

Successful total en bloc spondylectomy of the L3 vertebra with a paravertebral giant cell tumor following preoperative treatment with denosumab: a case report

BACKGROUND

Giant cell tumor is known to be a benign neoplasm that arises most commonly in the long bones, while cases in the spine are rare. Recently, denosumab, a monoclonal antibody that inhibits receptor activator of nuclear factor-kappa β ligand, has been used to treat patients with giant cell tumor. However, there are few reports of total en bloc spondylectomy being used for paravertebral giant cell tumor lesions following denosumab therapy.

CASE PRESENTATION

Our patient was a 20-year-old Japanese woman with a 4-month history of lower back pain. A spinal computed tomography scan and magnetic resonance imaging of her lumbar spine revealed an osteolytic lesion involving the L3 vertebral body, and the tumor extended toward the left side of the paravertebral soft tissue and into the left pedicle. The lesion was diagnosed as a giant cell tumor by needle biopsy. Denosumab treatment calcified the paravertebral giant cell tumor lesion and the tumor vertebral body was removed completely by total en bloc spondylectomy.

CONCLUSION

This case report describes a patient with a paravertebral giant cell tumor who was successfully treated by preoperative denosumab injection followed by total en bloc spondylectomy.

Surgical Treatment of Osteoporotic Vertebral Fracture with Neurological Deficit-A Nationwide Multicenter Study in Japan

Introduction

The prevalence of patients with osteoporosis continues to increase in aging societies, including Japan. The first choice for managing osteoporotic vertebral compression fracture (OVF) is conservative treatment. Failure in conservative treatment for OVF may lead to non-union or vertebral collapse, resulting in neurological deficit and subsequently requiring surgical intervention. This multicenter nationwide study in Japan was conducted to comprehensively understand the outcomes of surgical treatments for OVF non-union.

Methods

This multicenter, retrospective study included 403 patients (89 males, 314 females, mean age 73.8 ± 7.8 years, mean follow-up 3.9 ± 1.7 years) with neurological deficit due to vertebral collapse or non-union after OVF at T10-L5 who underwent fusion surgery with a minimum 1-year follow-up. Radiological and clinical outcomes at baseline and at the final follow-up (FU) were evaluated.

Results

OVF was present at a thoracolumbar junction such as T12 (124 patients) and L1 (117 patients). A majority of OVF occurred after a minor trauma, such as falling down (55.3%) or lifting objects (8.4%). Short segment fusion, including affected vertebra, was conducted (mean 4.0 ± 2.0 vertebrae) with 256.8 minutes of surgery and 676.1 g of blood loss. A posterior approach was employed in 86.6% of the patients, followed by a combined anterior and posterior (8.7%), and an anterior (4.7%) approach. Perioperative complications and implant failures were observed in 18.1% and 41.2%, respectively. VAS scores of low back pain (74.7 to 30.8 mm) and leg pain (56.8 to 20.7 mm) improved significantly at FU. Preoperatively, 52.6% of the patients were unable to walk and the rate of non-ambulatory patients decreased to 7.5% at FU.

Conclusions

This study demonstrated that substantial improvement in activity of daily living (ADL) was achieved by fusion surgery. Although there was a considerable rate of complications, fusion surgery is beneficial for elderly OVF patients with non-union.

Surgical outcomes of spinal fusion for osteoporotic thoracolumbar vertebral fractures in patients with Parkinson's disease: what is the impact of Parkinson's disease on surgical outcome?

BACKGROUND

To date, there have been little published data on surgical outcomes for patients with PD with thoracolumbar OVF. We conducted a retrospective multicenter study of registry data to investigate the outcomes of fusion surgery for patients with Parkinson's disease (PD) with osteoporotic vertebral fracture (OVF) in the thoracolumbar junction.

METHODS

Retrospectively registered data were collected from 27 universities and their affiliated hospitals in Japan. In total, 26 patients with PD (mean age, 76 years; 3 men and 23 women) with thoracolumbar OVF who underwent spinal fusion with a minimum of 2 years of follow-up were included (PD group). Surgical invasion, perioperative complications, radiographic sagittal alignment, mechanical failure (MF) related to instrumentation, and clinical outcomes were evaluated. A control group of 296 non-PD patients (non-PD group) matched for age, sex, distribution of surgical procedures, number of fused segments, and follow-up period were used for comparison.

RESULTS

The PD group showed higher rates of perioperative complications (p < 0.01) and frequency of delirium than the non-PD group (p < 0.01). There were no significant differences in the degree of kyphosis correction, frequency of MF, visual analog scale of the symptoms, and improvement according to the Japanese Orthopaedic Association scoring system between the two groups. However, the PD group showed a higher proportion of non-ambulators and dependent ambulators with walkers at the final follow-up (p < 0.01).

CONCLUSIONS

A similar surgical strategy can be applicable to patients with PD with OVF in the thoracolumbar junction. However, physicians should pay extra attention to intensive perioperative care to prevent various adverse events and implement a rehabilitation regimen to regain walking ability.

Novel Unidirectional Porous β-Tricalcium Phosphate Used as a Bone Substitute after Excision of Benign Bone Tumors of the Hand: A Case Series

Unidirectional porous β-tricalcium phosphate (UDPTCP; Affinos^®, Kuraray, Tokyo, Japan) has been in clinical use since 2015. Animal studies have confirmed the excellent potential of UDPTCP with regard to bone formation and material absorption. We present the first three clinical cases using UDPTCP as a bone substitute after curettage of benign bone tumors of the hand. All three patients were males, 29-, 30- and 81-years-old, two having a diagnosis of enchondroma and the other, a bone ganglion, with a pathological fracture identified in one case. Over a mean follow-up of 10 months, all patients achieved satisfactory clinical result, with no adverse events of UDPTCP noted. Radiographic evidence of good bone formation and material absorption was observable over the postoperative course. UDPTCP provided satisfactory clinical results, with good biocompatibility and fast resorption characteristics. Therefore, UDPTCP could provide a safe and reliable filling substitute for bone defects following curettage of small bone tumors.

Risk Factors for Proximal Junctional Fracture Following Fusion Surgery for Osteoporotic Vertebral Collapse with Delayed Neurological Deficits: A Retrospective Cohort Study of 403 Patients

Introduction

Approximately 3% of osteoporotic vertebral fractures develop osteoporotic vertebral collapse (OVC) with neurological deficits, and such patients are recommended to be treated surgically. However, a proximal junctional fracture (PJFr) following surgery for OVC can be a serious concern. Therefore, the aim of this study is to identify the incidence and risk factors of PJFr following fusion surgery for OVC.

Methods

This study retrospectively analyzed registry data collected from facilities belonging to the Japan Association of Spine Surgeons with Ambition (JASA) in 2016. We retrospectively analyzed 403 patients who suffered neurological deficits due to OVC below T10 and underwent corrective surgery; only those followed up for　≥2 years were included. Potential risk factors related to the PJFr and their cut-off values were calculated using multivariate logistic regression analysis and receiver operating characteristic (ROC) analysis.

Results

Sixty-three patients (15.6%) suffered PJFr during the follow-up (mean 45.7 months). In multivariate analysis, the grade of osteoporosis (grade 2, 3: adjusted odds ratio (aOR) 2.92; p=0.001) and lower instrumented vertebra (LIV) level (sacrum: aOR 6.75; p=0.003) were independent factors. ROC analysis demonstrated that lumbar bone mineral density (BMD) was a predictive factor (area under curve: 0.72, p=0.035) with optimal cut-off value of 0.61 g/cm² (sensitivity, 76.5%; specificity, 58.3%), but that of the hip was not (p=0.228).

Conclusions

PJFr was found in 16% cases within 4 years after surgery; independent risk factors were severe osteoporosis and extended fusion to the sacrum. The lumbar BMD with cut-off value 0.61 g/cm² may potentially predict PJFr. Our findings can help surgeons select perioperative adjuvant therapy, as well as a surgical strategy to prevent PJFr following surgery.

Formation of osteon-like structures in unidirectional porous hydroxyapatite substitute

Unidirectional porous hydroxyapatite (UDPHAp) bone substitute comprises a microstructure of cross‐sectionally oval pores with diameters ranging from 30 to 300 µm. Bone remodeling within the UDPHAp is expected upon implantation into bone; however, the mechanism and factors influencing this bone growth remain unclear. The objectives of the present study were to assess the vasculature and microstructure of newly formed bone and to determine how bone formation is affected by load transfer and UDPHAp pore size. Formation of osteon‐like structures, defined by the presence of lacunae, canaliculi and a central lumen containing capillaries, was observed within the implanted UDPHAp material in all animals after six weeks. The number of osteocytes and osteon‐like structures in areas adjacent to the cortex of recipient bone was significantly higher than in areas next to the medullary cavity throughout the recovery period. Notably, osteon‐like structures tended to form in smaller diameter pores. Continuous bone remodeling might be promoted by the rapid formation of unidirectional capillaries and the osteocyte lacunae‐canalicular system. Load transfer and smaller pore size could positively affect cortical bone regeneration. © 2018 The Authors Journal of Biomedical Materials Research Part B: Applied Biomaterials Published by Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 2665–2672, 2018.

Near-infrared fluorescence imaging with indocyanine green-lactosomes in a mouse model of rheumatoid arthritis

OBJECTIVES

The early diagnosis and treatment of rheumatoid arthritis (RA) is important to reduce joint destruction. Many of the current imaging techniques have disadvantages, such as the need for contrast agents and interpretation by specialists. Fluorescence imaging is an emerging technique that overcomes some of these problems. The aim of this study was to determine whether near-infrared (NIR) fluorescence imaging of indocyanine green (ICG)-lactosomes can detect joint inflammation in a mouse model of RA.

METHODS

Control and arthritic SKG/Jcl mice were injected with ICG alone or ICG-lactosomes and examined by NIR fluorescence imaging. Arthritis severity was assessed macroscopically and histopathologically.

RESULTS

ICG fluorescence was detected in the liver soon after injection and then decreased over the next several hours. ICG was not detected in the joints of control or arthritic mice. In contrast, ICG-lactosomes remained in mice for at least 48 h and accumulated specifically at inflamed joints. ICG-lactosome fluorescence was higher in arthritic versus normal joints at all times examined and was maximal at 24 h after injection.

CONCLUSIONS

NIR fluorescence imaging of ICG-lactosomes detects arthritic joints in a mouse model of RA. ICG-lactosomes may preferentially localize to inflamed joints via enhanced permeability and retention.

Tumor-selective near-infrared photodynamic therapy with novel indocyanine green-loaded nanocarrier delays paralysis in rats with spinal metastasis

BACKGROUND

Although recent advances in surgery have improved the quality of life of patients with spinal metastasis, local recurrence is still relatively common. Therefore, there is an urgent need for new surgical treatment options for metastatic spinal cancer. We previously described a novel nanocarrier loaded with indocyanine green (ICG), ICG-lactosome which exhibits tumor selectivity and is a potential near-infrared (NIR) fluorescence imaging agent for the diagnosis of spinal metastasis. The purpose of this study was to investigate the therapeutic effects of tumor-selective photodynamic therapy (PDT) with ICG-lactosome and NIR light irradiation in a rat model of spinal metastasis.

METHODS

Twenty-one Fischer 344 rats each with a single spinal metastasis in the L6 vertebral body were divided into 3 treatment groups: PDT with a low-concentration ICG-lactosome injection (6 rats), PDT with high-concentration ICG-lactosome injection (7 rats), and a group without ICG-lactosome injection (8 rats). All the animals received local NIR light irradiation with a total energy of 5 J (0.5 W for 10s).

RESULTS

Both the PDT groups injected with ICG-lactosome showed delayed deterioration of hind-limb paralysis compared with the group without ICG-lactosome.

CONCLUSION

This modified PDT procedure could be an effective local treatment for spinal metastasis.