Dynamics of atlantoaxial rotation related to age and sex: a cross-sectional study of 308 subjects.

BACKGROUND CONTEXT: Physiological ranges and dynamic changes of atlantoaxial rotation (ROTC1/2), total cervical spine rotation (ROTCs) and the percentage of ROTC1/2 from ROTCs (ROTCperc) for different age groups have not yet been investigated in a sufficiently sized cohort. Furthermore, it is not clear whether demographic variables such a sex, smoking status or diabetes affect ROTC1/2, ROTCs and ROTCperc. PURPOSE: Obtain physiological ranges of ROTC1/2, ROTCs and ROTCperc for different age groups and determine their age-based dynamics. Investigate whether ROTC1/2, ROTCs and ROTCperc are affected by sex, smoking status or diabetes. DESIGN: Observational cross-sectional study. PATIENT SAMPLE: Patients undergoing elective CT examinations of the head and neck region between August 2020 and January 2022. OUTCOME MEASURES: Ranges of motion of ROTC1/2, ROTCs and ROTCperc in degrees. METHODS: A total of 308 subjects underwent dynamic rotational CT examinations of the upper cervical spine. Patients were divided into three age categories A1 (27-49 years), A2 (50-69 years) and A3 (≥70 years). Category A3 was further divided into B1 (70-79 years) and B2 (≥80 years). Values of ROTC1/2, ROTCs and ROTCperc were compared between all age groups, males and females, smokers and nonsmokers, diabetics a nondiabetics. Dynamics of ROTC1/2, ROTCs related to age and sex were visualized using scatterplot and trendline models. RESULTS: ROTC1/2 significantly decreased from group A1 (64.4°) to B2 (46.7°) as did ROTCs from A1 (131.2°) to B2 (97.6°). No significant differences of ROTperc were found between groups A1-B2 with values oscillating between 49% and 51%. Smoking and diabetes did not significantly affect ROTC1/2, ROTCs and ROTCperc, females had significantly higher ROTCs than males. Males and females demonstrated a different dynamic of ROTC1/2 and ROTCs demonstrated by out scatterplot and trendline models. CONCLUSIONS: Both ROTC1/2 and ROTCs significantly decrease with age, whereas ROTCperc remains stable. Females demonstrated higher ROTCs and their decrease of ROTC1/2 and ROTCs occurred in higher age groups compared to males. The functional repercussions atlantoaxial fusion are variable based on patient age and sex and should be taken into account prior to surgery.

Anthropometry of the human calcaneus and orientation of the articular facet for the cuboid bone as a basis for anatomically correct positioning of osteosynthetic screws in fracture treatment.

PURPOSE: Fractures of the calcaneus are reported most commonly in the tarsal region. Their incidence is highest among active people in productive age. As such, optimal treatment can have vast implications for patients. The study aimed to compare calcaneal proportions of the Czech population in the last centuries to present day, for a precise choice and positioning of the osteosynthetic material, and its safe implantation in the anterior part of the calcaneus. Furthermore, we describe the frequency of the calcaneocuboid joint involvement in calcaneal fractures. METHODS: We obtained 69 macerated (dry) human calcanei from anatomical collections along with multiplanar reconstructions obtained from 43 serial CT scans from patients with injuries other than calcaneal fractures. Specimens were measured using a modified set of Bidmos et al. criteria (2006). Two groups (CT scans of macerated specimens and patients' CT scans) were statistically evaluated and compared with the help of an experienced statistician. Furthermore, scans of 80 surgically treated patients were retrospectively assessed for calcaneocuboid joint involvement. RESULTS: The median tilt of the calcaneocuboid joint in the transverse plane was 67° in the anatomical specimens and 72° in the multiplanar reconstructed CT scans taken from patients with intact tarsal regions. These results suggest that the length of screws should be ideally in the range between 21.3 and 25mm. In 47.3% of the patients presenting with a fractured calcaneus, the calcaneocuboid joint was involved. There was a statistically significant difference in most of the variables observed between the two groups. CONCLUSION: As the calcaneocuboid joint involvement appears to be present in up to 50% of cases, adequate care should be taken. To maximize the biomechanical properties of the construct and to minimize the risks, our findings suggest the screws should be at an inner tilt of 68-74° from the lateral calcaneal wall and be of 23.5-26.2mm length. However, due to differences between the two groups and the small sample size, further investigation is needed.

Modified Methacrylate Hydrogels Improve Tissue Repair after Spinal Cord Injury.

Methacrylate hydrogels have been extensively used as bridging scaffolds in experimental spinal cord injury (SCI) research. As synthetic materials, they can be modified, which leads to improved bridging of the lesion. Fibronectin, a glycoprotein of the extracellular matrix produced by reactive astrocytes after SCI, is known to promote cell adhesion. We implanted 3 methacrylate hydrogels: a scaffold based on hydroxypropylmethacrylamid (HPMA), 2-hydroxyethylmethacrylate (HEMA) and a HEMA hydrogel with an attached fibronectin (HEMA-Fn) in an experimental model of acute SCI in rats. The animals underwent functional evaluation once a week and the spinal cords were histologically assessed 3 months after hydrogel implantation. We found that both the HPMA and the HEMA-Fn hydrogel scaffolds lead to partial sensory improvement compared to control animals and animals treated with plain HEMA scaffold. The HPMA scaffold showed an increased connective tissue infiltration compared to plain HEMA hydrogels. There was a tendency towards connective tissue infiltration and higher blood vessel ingrowth in the HEMA-Fn scaffold. HPMA hydrogels showed a significantly increased axonal ingrowth compared to HEMA-Fn and plain HEMA; while there were some neurofilaments in the peripheral as well as the central region of the HEMA-Fn scaffold, no neurofilaments were found in plain HEMA hydrogels. In conclusion, HPMA hydrogel as well as the HEMA-Fn scaffold showed better bridging qualities compared to the plain HEMA hydrogel, which resulted in very limited partial sensory improvement.

Dynamics of tissue ingrowth in SIKVAV-modified highly superporous PHEMA scaffolds with oriented pores after bridging a spinal cord transection.

While many types of biomaterials have been evaluated in experimental spinal cord injury (SCI) research, little is known about the time-related dynamics of the tissue infiltration of these scaffolds. We analyzed the ingrowth of connective tissue, axons and blood vessels inside the superporous poly (2-hydroxyethyl methacrylate) hydrogel with oriented pores. The hydrogels, either plain or seeded with mesenchymal stem cells (MSCs), were implanted in spinal cord transection at the level of Th8. The animals were sacrificed at days 2, 7, 14, 28, 49 and 6 months after SCI and histologically evaluated. We found that within the first week, the hydrogels were already infiltrated with connective tissue and blood vessels, which remained stable for the next 6 weeks. Axons slowly and gradually infiltrated the hydrogel within the first month, after which the numbers became stable. Six months after SCI we observed rare axons crossing the hydrogel bridge and infiltrating the caudal stump. There was no difference in the tissue infiltration between the plain hydrogels and those seeded with MSCs. We conclude that while connective tissue and blood vessels quickly infiltrate the scaffold within the first week, axons show a rather gradual infiltration over the first month, and this is not facilitated by the presence of MSCs inside the hydrogel pores. Further research which is focused on the permissive micro-environment of the hydrogel scaffold is needed, to promote continuous and long-lasting tissue regeneration across the spinal cord lesion.

Chemical angioplasty with spasmolytics for vasospasm after subarachnoid hemorrhage.

BACKGROUND: Clinically symptomatic vasospasm leading to delayed ischemic neurological deficits occurs in up to 30% of patients with subarachnoid hemorrhage (SAH). Vasospasm can result in a serious decline in clinical conditions of patients with SAH, yet the algorithm for vasospasm treatment and prevention remains unclear. Intra-arterial administration of vasodilators is one of the modalities used for vasospasm therapy. METHODS: Over the last 7 years, we have treated 27 female and 7 male patients with vasospasm using intra-arterial administration of either nimodipine or milrinone; all had suffered aneurysm rupture. Of these patients, 28 were treated surgically (clip), and 6 patients had their aneurysm coiled. Spasmolytics were applied from day 2 to day 18 after rupture. RESULTS: Of the 53 procedures, angiographic improvement was documented in 92% of cases with a mean flow velocity decrease of 65 cm/s. Brain metabolism changes were monitored after the procedure. The highest level of immediate clinical improvement was observed in conscious patients with a focal neurological deficit (aphasia, hemiparesis). Overall clinical outcomes (Glasgow outcome scale, GOS) were as follows: GOS 5 (12 patients), GOS 4 (5 patients), GOS 3 (5 patients), GOS 2 (6 patients), and GOS 1 (6 patients). CONCLUSIONS: Intra-arterial administration of spasmolytics is a safe and potent method of vasospasm treatment. It is most effective when applied to conscious patients with a focal deficit. For unconscious patients, its therapeutic benefits are inconclusive. Patients in severe clinical states would further require use of other diagnostic tools such as multimodal brain monitoring to complement vasospasm therapy.

Management of posterior inferior cerebellar artery aneurysms: What factors play the most important role in outcome?

BACKGROUND: Posterior inferior cerebellar artery (PICA) aneurysms are an uncommon, heterogeneous group of aneurysms with poorer clinical outcomes compared to other intracranial aneurysms. We performed a multicenter retrospective study to analyze the outcome in a large series of patients treated with modern microsurgical and endovascular techniques. METHODS: Records of 94 patients treated for PICA aneurysms between 2000 and 2015 at three large tertiary referral centers were retrospectively reviewed. RESULTS: Eighty-three patients met inclusion criteria and of these, two died before treatment, leaving 81 treated patients (43 underwent endovascular and 38 surgical treatment). Among patients treated endovascularly, procedure-related complications occurred in four cases (11.8%). Six patients (19.4%) suffered from complications directly associated with surgery. Recurrences occurred in 0% of surgical and in 16.3% of endovascularly treated patients, requiring treatment. Patients with unruptured asymptomatic aneurysms had good outcomes. In the group of 67 ruptured aneurysms, 16 endovascularly (47.1%) and 15 surgically (48.4%) treated patients had modified Rankin scale (mRS) scores of 3-6. Of patients in poor neurological condition (Hunt & Hess (H&H) IV-V at admission), 84.6% suffered a poor clinical outcome. Fifty percent of patients with distal and 31.9% patients with proximal ruptured PICA aneurysms suffered a poor neurological outcome. CONCLUSIONS: This study of PICA aneurysms demonstrates that results of both treatment modalities are comparable. However, endovascular treatment is associated with higher risks of recurrence, requiring additional treatment. Outcomes were mostly impacted by clinical state at admission.

Adjusting the chemical and physical properties of hydrogels leads to improved stem cell survival and tissue ingrowth in spinal cord injury reconstruction: a comparative study of four methacrylate hydrogels.

Currently, there is no effective strategy for the treatment of spinal cord injury (SCI). A suitable combination of modern hydrogel materials, modified to effectively bridge the lesion cavity, combined with appropriate stem cell therapy seems to be a promising approach to repair spinal cord damage. We demonstrate the synergic effect of porosity and surface modification of hydrogels on mesenchymal stem cell (MSC) adhesiveness in vitro and their in vivo survival in an experimental model of SCI. MSCs were seeded on four different hydrogels: hydroxypropylmethacrylate-RGD prepared by heterophase separation (HPMA-HS-RGD) and three other hydrogels polymerized in the presence of a solid porogen: HPMA-SP, HPMA-SP-RGD, and hydroxy ethyl methacrylate [2-(methacryloyloxy)ethyl] trimethylammonium chloride (HEMA-MOETACl). Their adhesion capability and cell survival were evaluated at 1, 7, and 14 days after the seeding of MSCs on the hydrogel scaffolds. The cell-polymer scaffolds were then implanted into hemisected rat spinal cord, and MSC survival in vivo and the ingrowth of endogenous tissue elements were evaluated 1 month after implantation. In vitro data demonstrated that HEMA-MOETACl and HPMA-SP-RGD hydrogels were superior in the number of cells attached. In vivo, the highest cell survival was found in the HEMA-MOETACl hydrogels; however, only a small ingrowth of blood vessels and axons was observed. Both HPMA-SP and HPMA-SP-RGD hydrogels showed better survival of MSCs compared with the HPMA-HS-RGD hydrogel. The RGD sequence attached to both types of HPMA hydrogels significantly influenced the number of blood vessels inside the implanted hydrogels. Further, the porous structure of HPMA-SP hydrogels promoted a statistically significant greater ingrowth of axons and less connective tissue elements into the implant. Our results demonstrate that the physical and chemical properties of the HPMA-SP-RGD hydrogel show the best combination for bridging a spinal cord lesion, while the HEMA-MOETACl hydrogel serves as the best carrier of MSCs.

Treating spinal cord injury in rats with a combination of human fetal neural stem cells and hydrogels modified with serotonin.

Currently, there is no effective strategy for the treatment of spinal cord injury (SCI). A combination of biomaterials and stem cell therapy seems to be a promising approach to increase regenerative potential after SCI. We evaluated the use of a cellpolymer construct based on a combination of the conditionally immortalized spinal progenitor cell line SPC-01_GFP3, derived from human fetal spinal cord tissue, with a serotonin-modified poly(2-hydroxyethyl methacrylate) hydrogel (pHEMA-5HT). We compared the effect of treatment with a pHEMA-5HT hydrogel seeded with SPC-01_GFP3 cells, treatment with a pHEMA-5HT only and no treatment on functional outcome and tissue reconstruction in hemisected rats. Prior to transplantation the cell-polymer construct displayed a high potential to support the growth, proliferation and differentiation of SPC-01 cells in vitro. One month after surgery, combined hydrogel-cell treatment reduced astrogliosis and tissue atrophy and increased axonal and blood vessel ingrowth into the implant; however, two months later only the ingrowth of blood vessels remained increased. SPC-01_GFP3 cells survived well in vivo and expressed advanced markers of neuronal differentiation. However, a majority of the transplanted cells migrated out of the lesion and only rarely remained in the hydrogel. No differences among the groups in motor or sensory recovery were observed. Despite the support of the hydrogel as a cell carrier in vitro, and good results in vivo one month postsurgery, there was only a small effect on long term recovery, mainly due to the limited ability of the hydrogels to support the in vivo growth and differentiation of cells within the implant. Further modifications will be necessary to achieve stable long term improvement in functional outcome.