Single-level ossified ligamentum flavum causing a holocord syrinx: illustrative case

BACKGROUND

Syringomyelia is a neurological disorder that is caused by abnormal cerebrospinal fluid flow or circulation. It is an incidental finding in most cases, predominantly presenting with sensory symptoms of insensitivity to pain and temperature. Spinal ossified ligamentum flavum (OLF) leading to syringomyelia is one of the rare causes. The authors report an unusual case of syringomyelia due to a thoracic OLF.

OBSERVATIONS

A 54-year-old female presented with backache, difficulty walking, spasticity in the bilateral lower limbs, tingling sensation in the bilateral lower limbs, and paraparesis for 5 years. Her radiological investigations were suggestive of an OLF causing a syrinx. She underwent laminectomy, and her syrinx resolved on subsequent follow-up.

LESSONS

A syrinx due to a single-level OLF is rare, and this uncommon cause should be kept in mind while formulating treatment plans.

Piezo1 involves in intracellular osteogenic transformation signal to promote the ossification of ligamentum flavum

Ectopic osteogenesis refers to the occurrence of osteoblasts in soft tissues other than bone tissue and the formation of bone tissue. The ligamentum flavum is an essential connecting structure between adjacent vertebral lamina, which participates in the formation of the vertebral canal's posterior wall and maintains the vertebral body's stability. Ossification of the ligamentum flavum (OLF) is one of the manifestations of systemic ossification of the spinal ligaments and one of the degenerative diseases related to the spine. However, there is a lack of research on the expression and biological function of Piezo1 in ligamentum flavum. Whether Piezo1 participates in the development of OLF is still unclear. The FX-5000C cell or tissue pressure culture and real-time observation and analysis system was applied to stretch ligamentum flavum cells to detect the expression of mechanical stress channel and osteogenic markers after the effect of different stretching durations. The results showed elevated expression of mechanical stress channel Piezo1 and osteogenic markers with the effect of tensile time duration. In conclusion, Piezo1 involves in intracellular osteogenic transformation signal to promote the ossification of ligamentum flavum. An approved explanatory model and further research will be required in the future.

A rare case of giant calcified thoracic disc herniation, OPLL and OLF: how I do it

BACKGROUND

Thoracic myelopathy can have different aetiologies. Based on the location and on the nature of spinal cord compression, different surgical approaches may be indicated.

METHOD

We present a rare case of thoracic myelopathy caused by the coexistence of a giant disc herniation, OPLL and OLF, and we describe the surgical approach, with a focus on technical nuances and strategies to avoid complications.

CONCLUSION

Careful presurgical planning and microsurgery are fundamental in achieving a satisfactory spinal cord decompression. IONM, endoscopy-assisted microsurgery and intraoperative navigation can enhance the safety of surgery and the extent of safe surgical decompression.

BMP2 Modified by the m6A Demethylation Enzyme ALKBH5 in the Ossification of the Ligamentum Flavum Through the AKT Signaling Pathway

Ossification of the ligamentum flavum (OLF) is characterized by a process of ectopic bone formation in the ligamentum flavum. The definitive pathophysiology of OLF still remains unclear, but the epigenetic m6A modification plays an important role in OLF. In addition, no studies have reported the function of ALKBH5 in OLF development. In this study, we investigated the function of the m6A demethylation enzyme ALKBH5 in OLF. To evaluate the function of ALKBH5, OLF tissues and normal ligamentum flavum tissues were collected. In vitro methods, including HE, IHC and western blotting assays, were used to evaluate the association of ALKBH5 with OLF. In addition, we verified the effects of ALKBH5 on osteogenesis using alizarin red and ALP staining. MeRIP q-PCR was performed to investigate the methylation level of BMP2. Moreover, the mechanism of ALKBH5-mediated regulation of the ossification of the ligamentum flavum cells through the AKT signaling pathway was also verified. The present study showed that the expression of ALKBH5 increased in OLF tissues. The overexpression of ALKBH5 increased the expression of osteogenic genes and promoted the ossification of ligamentum flavum cells. Furthermore, BMP2 was significantly enriched in the ligamentum flavum cells of the anti-m6A group compared with those of the IgG group. The overexpression of ALKBH5 led to the activation of p-AKT, and BMP2 was regulated by ALKBH5 through the AKT signaling pathway. ALKBH5 promoted the osteogenesis of the ligamentum flavum cells through BMP2 demethylation and AKT activation. ALKBH5 was shown to be an important demethylation enzyme in OLF development.

Repeated recurrence of thoracic spine stenosis following decompression alone for ossification of the ligamentum flavum: case report

Ossification of the ligamentum flavum (OLF) is a well-recognized but rare cause of thoracic myelopathy. Its subtle and variable clinical presentation often makes the diagnosis challenging. The treatment of symptomatic OLF requires surgical intervention, with the most common surgical procedure being a posterior decompression with or without instrumentation. Recurrence of ossification and stenosis after surgery is rare and usually occurs at the same intervertebral level. Multiple recurrences of ossification and stenosis are exceptionally rare. The authors report the case of OLF in a 60-year-old man who experienced recurrence of ossification and stenosis twice after posterior decompression surgeries alone. The patient was ultimately treated with revision decompression and instrumented fusion. The authors also present a pertinent review of the literature.

Prevalence and distribution of ossification of the supra/interspinous ligaments in symptomatic patients with cervical ossification of the posterior longitudinal ligament of the spine: a CT-based multicenter cross-sectional study

Background

Supra/interspinous ligaments connect adjacent spinous processes and act as a stabilizer of the spine. As with other spinal ligaments, it can become ossified. However, few report have discussed ossification supra/interspinous ligaments (OSIL), so its epidemiology remains unknown. We therefore aimed to investigate the prevalence and distribution of OSIL in symptomatic patients with cervical ossification of the posterior longitudinal ligament (OPLL).

Methods

The participants of our study were symptomatic patients with cervical OPLL who were diagnosed by standard radiographs of the cervical spine. The whole spine CT data as well as clinical parameters such as age and sex were obtained from 20 institutions belong to the Japanese Multicenter Research Organization for Ossification of the Spinal Ligament (JOSL). The prevalence and distribution of OSIL and the association between OSIL and clinical parameters were reviewed. The sum of the levels involved by OPLL (OP-index) and OSIL (OSI-index) as well as the prevalence of ossification of the nuchal ligament (ONL) were also investigated.

Results

A total of 234 patients with a mean age of 65 years was recruited. The CT-based evidence of OSIL was noted in 68 (54 males and 14 females) patients (29%). The distribution of OSIL showed a significant thoracic preponderance. In OSIL-positive patients, single-level involvement was noted in 19 cases (28%), whereas 49 cases (72%) presented multi-level involvement. We found a significant positive correlation between the OP-index grade and OSI-index. ONL was noted at a significantly higher rate in OSIL-positive patients compared to negative patients.

Conclusions

The prevalence of OSIL in symptomatic patients with cervical OPLL was 29%. The distribution of OSIL showed a significant thoracic preponderance.

Involvement of chymase in allergic conjunctivitis of guinea pigs

It has been reported that chymase activity was increased in allergic conjunctivitis patients and this activity was correlated with the severity of the disease. However, the precise roles of chymase in allergic conjunctivitis are unclear, and whether chymase inhibitors are effective for allergic conjunctivitis has not been reported even in experimental animal models. In this study, the roles of chymase in the pathogenesis were evaluated using a selective chymase inhibitor, ONO-WH-236, in a guinea pig model of allergic conjunctivitis induced by cedar pollen. Sensitized guinea pigs were challenged by the pollen, followed by assessing redness and edema in the conjuntiva, and counting the frequency of eye scratching as an itch-associated response. Treatment with the ONO-WH-236 (40 and 80 mg/kg, p.o.) dose-dependently inhibited the induction of redness, edema and scratching behavior. An anti-histaminic drug, ketotifen (3 mg/kg, p.o.), also significantly inhibited conjunctivitis symptoms. Chymase activity was increased in ophthalmic lavage fluid immediately after the pollen challenge. The increase in chymase activity was inhibited by in vivo treatment with ONO-WH-236. Interestingly, increased histamine in the ophthalmic lavage fluid immediately after the challenge was also inhibited by the chymase inhibitor. Administration of human recombinant chymase by eye dropping (0.09 and 0.9 μg/eye) dose-dependently induced scratching behavior, which was inhibited by not only ONO-WH-236 but also ketotifen; however, chymase administration induced only weak redness in the conjunctiva, which was resistant to treatment with anti-histaminic drugs. In conclusion, it was suggested that chymase was released from mast cells after antigen challenge, followed by the induction of conjunctivitis symptoms through histamine release from mast cells. Thus, chymase could be a potential target for pharmacotherapy for allergic conjunctivitis.

Ossification of the ligamentum flavum of the lumbosacral spine in the Polish hospitalized population - a prospective cohort study

AIM

The aim of this study was to assess the prevalence, clinical features and distribution of lumbosacral ossifications of the ligamentum flavum (OLF), using MRI, CT and microCT, in hospitalized Polish patients.

METHODS

Patients were recruited prospectively between January 2011 and January 2013. Patients were further qualified to the study group only if CT or MRI of the lumbosacral region detected OLF. Level of OLF excision was determined by the localization of spinal stenosis. After excision the LF fragments containing OLF were stored in a 4% solution of formaldehyde until microCT assessment.

RESULTS

A total of 184 agreed to take part in the study. In 50 patients (27.2%) OLF were found. Thus, the study group consisted of 17 women (34%) and 33 men, with a mean age of 55.4 ± 17.2 years. OLF occurred more often in men (66%) than in women (34%) (p = 0.0014). The most common site for the localization of OLF in women, as well as in men was the L5/S1 level (60% and 53.3% respectively). The mean volume of OLF was 3.87 ± 5.27 mm3 (4.66 ± 5.71 mm3 vs. 1.27 ± 2.19 mm3, in men and women respectively; p = 0.023). The LF were thickened in 21 (42%) patients. The mean volume of OLF in patients with normal LF was 4.78 ± 5.95 mm3 and in patients with thickened LF 5.33 ± 6.10 mm3 (p = 0.75).

CONCLUSIONS

The prevalence of lumbosacral OLF in the Polish hospitalized population is very high. The most common site of their localization is the L5/S1 level. LF thickening is not associated with OLF formation.