Engineering bone tissue from human embryonic stem cells

In extensive bone defects, tissue damage and hypoxia lead to cell death, resulting in slow and incomplete healing. Human embryonic stem cells (hESC) can give rise to all specialized lineages found in healthy bone and are therefore uniquely suited to aid regeneration of damaged bone. We show that the cultivation of hESC-derived mesenchymal progenitors on 3D osteoconductive scaffolds in bioreactors with medium perfusion leads to the formation of large and compact bone constructs. Notably, the implantation of engineered bone in immunodeficient mice for 8 wk resulted in the maintenance and maturation of bone matrix, without the formation of teratomas that is consistently observed when undifferentiated hESCs are implanted, alone or in bone scaffolds. Our study provides a proof of principle that tissue-engineering protocols can be successfully applied to hESC progenitors to grow bone grafts for use in basic and translational studies.     

Estimated low risk of rupture of small-sized unruptured intracranial aneurysms (UIAs) in relation to intracranial aneurysms in patients with subarachnoid haemorrhage

Objective

International guidelines for the management of unruptured intracranial aneurysms (UIAs) recommend observation in aneurysms <10 mm due to the estimated low risk of rupture. The aim of our study was analyse the data of recently treated patients with ruptured cerebral aneurysms with the special focus on size and configuration in view of the frequency scale in a daily routine setting.

Methods

We reviewed the data of all patients with aneurysmal subarachnoid haemorrhage (SAH) during the last 24 months at our institution. Configuration and size of the aneurysms were measured. Clinical data were collected using the following classifications for analysis: Hunt and Hess (H&H), modified Rankin Scale (mRS) and Fisher classification.

Results

Data of 135 patients with aneurysmal SAH (98 women, 37 men; ratio 2.6:1) were analysed. Analysis showed that 19 aneurysms (14 %) were >10 mm (mean size, 19.2 mm) and 116 aneurysms (85.9 %) <10 mm (mean size, 6.2 mm). In total, 112 were categorised as berry-like configured aneurysms (n?=?113 <10 mm, n?=?3 >10 mm), 18 as multi-lobar (n?=?16 <10 mm, n?=?2 >10 mm) and 5 as fusiform (n?=?4 <10 mm, n?=?1, >10 mm).

Conclusion

Since the results of our study showed that the majority of the aneurysms are <10 mm (mean, 6.2 mm), it is justified to challenge the recommendations of the international guidelines in a daily routine setting. We believe that the published data are not convincing enough to play a guidance role in daily routine. Due to improving surgical and endovascular techniques with satisfying results and the high number of ruptured small aneurysms, we believe a change in attitude in management of small-sized aneurysms is needed. Further diagnostic models are needed to determine the risk of rupture of intracranial aneurysms properly to obtain adequate treatment for UIAs.     

Periprosthetic bone mineral density after total hip arthroplasty with an AMIStem or Quadra femoral component performed by a minimally invasive anterior approach (AMIS): a prospective randomized clinical dual-energy X-ray absorptiometry study

Introduction

This prospective 12 months of dual-energy X-ray absorptiometry (DEXA) study evaluated differences in periprosthetic bone mineral density in 40 patients undergoing cementless total hip arthroplasty (THA) by a minimally invasive anterior approach (AMIS), using Medacta AMIStem or Quadra stems. Both stems are straight rectangular. AMIStem shows reduced lateral flare and length in comparison to Quadra.

Objectives

The main goal of the study is to verify if bone mineral density is equivalent following THA with the AMIStem and Quadra femoral components.

Methods

Forty patients were randomly allocated to the Quadra and AMIStem groups. Three patients were lost to follow-up because they moved to another town, and revision surgery was performed on one patient due to periprosthetic fracture after a car accident. Patients were examined clinically and underwent DEXA preoperatively and at 1 week, 6 weeks, 6 months, and 1 year after THA. Patients enrolled had no preexisting lower limb arthroplasty and no osteoporosis.

Results

Harris hip score increased significantly for Quadra stem 5.3?±?14.1 and AMIStem 41.0?±?13.4. The high-activity hip score increased significantly for Quadra stem 3.8 ±2.2 and AMIStem 4.1?±?2.4. Considering 0.15 mg/cm² as an acceptable difference, bone mineral density for AMIStem and Quadra groups was statistically equivalent. A limited remodeling process with slight bone loss in the proximal calcar region R7, as expected after implantation of uncemented components, was observed for both stems.

Conclusions

The study demonstrates that the two stems are statistically equivalent in all zones at all time points investigated.     

Symptomatic spinal cavernous malformations: indication for microsurgical treatment and outcome

Purpose  

We demonstrate clinical features, therapy and outcome of 14 patients with symptomatic spinal cavernous malformations (CM).