Treatment of Capitellum Fracture with Chronic Radial Head Dislocation.

We encountered a case of capitellum fracture with radial head dislocation in which it was challenging to diagnose whether the dislocation was coincident with the fracture or this was chronic dislocation that presented before the fracture. Chronic radial head dislocation may be congenital or could occur in patients with untreated post-traumatic dislocation, although diagnosis is particularly challenging if the radial head dislocation is unilateral. Classical capitellum fracture involves anterosuperior bone fragment dislocation. However, in the present case, the bone fragment was present beneath the radial head, which suggests chronic radial head dislocation. When the bone fragment appears in a different position than usual, every effort should be made to understand the pathophysiology by reviewing the mechanism of onset, disease history, and imaging.

Spinal surgery following renal transplantation.

BACKGROUND: With the improvement in postoperative care for renal transplant patients, the number of patients requiring spinal surgery after renal transplantation has been increasing. However, there have been only a few reports describing the results of spinal surgery in renal transplant recipients. In this study, we investigated the results of spine surgery in renal transplant recipients. METHODS: A total of 37 renal transplant recipients who underwent spinal surgery in our hospital between April 2003 and July 2012 were included in this study. RESULTS: Perioperative complications were observed in 6 cases (16.2%). Two of them (5.3%) were general complications including duodenal ulcer and acute renal failure. The other four complications (10.8%) were directly related to surgery, namely, epidural hematoma, neurological deterioration and two surgical site infections. No patient required permanent hemodialysis postoperatively. Twenty-five fusion surgeries were performed and pseudoarthrosis was observed in 3 cases (12.0%). CONCLUSION: Spinal surgery in renal transplant recipients can be performed without major complications or requirement for permanent hemodialysis postoperatively. Our data also showed a high rate of surgical site infection and pseudoarthrosis after fusion surgery.

Pycnodysostosis with Multi-Segmental Spinal Canal Stenosis due to Ossification of the Yellow Ligament.

Pycnodysostosis is an autosomal recessive disorder characterized by osteosclerosis, small stature, acro-osteolysis of the distal phalanges, loss of the mandibular angle, separated cranial sutures with open fontanels, and frequent fractures. One identified cause of the disease is reduced activity of the cysteine protease cathepsin K. A 48-year-old woman with a history of frequent fractures presented with a severe gait disturbance. Radiography, computed tomography, magnetic resonance imaging, and gene analysis were performed. Physical examination revealed open fontanels, and radiographs showed increased bone density. DNA sequence analysis revealed a deletion mutation of the cathepsin K gene. We diagnosed pycnodysostosis based on these findings. The magnetic resonance and computed tomography images demonstrated multilevel spinal canal stenosis due to ossification of the yellow ligament. We performed a laminectomy, and the patient's neurological signs and symptoms improved. To our knowledge, this is the first case of pycnodysostosis with ossification of the yellow ligament.

Drop metastasis of adrenocorticotropic hormone-producing pituitary carcinoma to the cauda equina.

The diagnosis of pituitary carcinoma cannot be made easily histologically, and most cases of pituitary carcinoma are diagnosed only after the clinical detection of metastasis. Distant metastasis of pituitary tumor occurs in 0.1% to 0.2% of cases and has been reported in the liver, bone and central nervous system, with only one case of metastasis to the cauda equine reported. This study describes a rare case of the drop metastasis of adrenocorticotropic hormone-producing pituitary adenocarcinoma to the cauda equina, causing cauda equina syndrome.

Low parathyroid hormone levels in patients who underwent/would undergo hemodialysis result in bone graft failure after posterolateral fusion.

STUDY DESIGN: Case series. OBJECTIVE: To reveal the association between levels of parathyroid hormone (PTH) and outcome of bone fusion in patients who underwent/would undergo hemodialysis. SUMMARY OF BACKGROUND DATA: Among the different bone lesions observed in patients who underwent/would undergo hemodialysis, adynamic bone disease is regarded as a factor associated with bone graft failure because of severely reduced bone turnover. Although PTH levels reflect the pathological findings of bone lesions in patients who underwent/would undergo hemodialysis, the relationship between PTH levels and the outcome of bone fusion in patients who underwent/would undergo hemodialysis has not been investigated. METHODS: Patients who underwent/would undergo hemodialysis (n = 48) with lumbar spine lesion underwent posterolateral spinal fusion with instrumentation. The outcome of bone fusion was assessed radiographically 12 months after surgery, and sensitivity and specificity were determined using preoperative PTH levels as the standard. RESULTS: A significant difference in PTH levels was observed between the good fusion (mean, 235.4 pg/mL) and poor fusion (mean, 100.0 pg/mL) groups. The intersection of the sensitivity and specificity plots, generated using preoperative PTH levels, was 150 pg/mL, and the area under the receiver operating characteristic curve was 0.72. CONCLUSION: Low PTH levels are a risk factor for bone graft failure in patients who underwent/would undergo hemodialysis. Accordingly, PTH level can be a useful predictor of the outcome of bone fusion. LEVEL OF EVIDENCE: 4.

Relation between atlantoaxial (C1/2) and cervical alignment (C2-C7) angles with Magerl and Brooks techniques for atlantoaxial subluxation in rheumatoid arthritis.

BACKGROUND: A few studies have reported the relation between the atlantoaxial (C1/2) angle and cervical alignment (C2-C7) angle after a Magerl and Brooks (M&B) surgical procedure to treat atlantoaxial subluxation (AAS) in patients with rheumatoid arthritis (RA). However, no study has examined an optimum preoperative C1/2 angle reduction. We aimed to assess the relation between the C1/2 angle reduction and the C2-C7 angle change in patients with progressive RA who underwent the M&B procedure. METHODS: We retrospectively analyzed the relation between the preoperative C1/2 angle and C2-C7 angle in 28 consecutive RA patients using their clinical and radiological data. Differences in the preoperative and postoperative C1/2 and C2-C7 angles were detected. Correlations of these angles and the reduced degree of angles were examined. The Ranawat grading scale and Japanese Orthopaedic Association (JOA) scores were used to determine myelopathy. Pain was categorized into five categories according to severity. Clinical and X-ray evaluations were collected before surgery, at 3 and/or 6 months after surgery, and at final follow-up. RESULTS: Clinical symptoms, Ranawat grade, and JOA scores improved postoperatively, and patients achieved bony union within 3 months. We observed a strong and significant correlation between the reduced C1/2 angle and the change in the C2-C7 angle. Patients with a preoperative C1/2 angle of <20 degrees had markedly reduced cervical lordotic angle but this condition was not seen in patients with a preoperative C1/2 angle of >or=20 degrees . The optimum C1/2 angle was estimated as [20 degrees - (preoperative C1/2 angle)] in patients with a C1/2 angle <20 degrees or as an in situ angle in patients with a C1/2 angle of >or=20 degrees . CONCLUSIONS: Surgeons performing the M&B procedure need to select patients carefully and avoid complete or overreduction of the C1/2 angle to prevent serious postoperative SAS and myelopathy.

Abolished interaction of NUB1 with mutant AIPL1 involved in Leber congenital amaurosis.

Leber congenital amaurosis (LCA) is often considered the most severe inherited retinopathy, and AIPL1 was the fourth gene identified as associated with LCA. Although the function of AIPL1 is unknown, it has been reported to interact with NUB1. Here, we searched for a NUB1-binding site on AIPL1 and located it between amino acid residues 181 and 330 in AIPL1. Importantly, many LCA-associated mutations of AIPL1 have been found at this site. Hence, we hypothesized that the interaction between NUB1 and AIPL1 is affected in patients with LCA. To test this possibility, we used three different assays to investigate the interaction between NUB1 and the AIPL1 mutants associated with LCA. Some of the AIPL1 mutants did not interact with NUB1, suggesting that abolishment of this interaction is involved in the pathogenesis of LCA. Other AIPL1 mutants, however, did interact with NUB1, suggesting that other molecules are also involved in the pathogenesis.

pVHL-independent ubiquitination of HIF1alpha and its stabilization by cobalt ion.

Recent studies have shown that hypoxia-inducible factor1alpha (HIF1alpha) is ubiquitinated by an E3-ligase complex containing von Hippel-Lindau gene product (pVHL) after which it is targeted for proteasomal degradation. In this study, we showed that HIF1alpha was stabilized in the pVHL-deficient cell line 786-0 treated with a proteasome inhibitor or Co(2+). This suggests that HIF1alpha is also ubiquitinated by a pVHL-independent pathway and that its stability is regulated by Co(2+). Indeed, using the COS cell expression system, we confirmed that HIF1alpha is ubiquitinated at the N-terminal region by a pVHL-independent pathway and that its degradation is inhibited by Co(2+). We also demonstrated that Co(2+) binds to both PAS domains in the N-terminal region of HIF1alpha. These observations imply that the stability of HIF1alpha is regulated by an additional pathway through the cobalt binding of PAS domains.

Cobalt- and nickel-binding property of cullin-2.

Treatment with divalent metal ions such as cobalt (Co(2+)) or nickel (Ni(2+)) result in the stabilization of hypoxia-inducible factor-1alpha (HIF1alpha). Recently, HIF1alpha was shown to be ubiquitinated by an E3-ligase complex and be subsequently targeted for proteasomal degradation. In this study, we demonstrated that Co(2+) and Ni(2+) specifically bind to cullin-2. Mutant analysis revealed that cullin-2 possesses at least three sites for the binding. Furthermore, fluorescence spectroscopy revealed that only Co(2+) and Ni(2+) have the binding activity to cullin-2, but other metal ions, including Cu(2+), Ca(2+), Mg(2+), Mn(2+), and Zn(2+), did not. Finally, we found that Co(2+) and Ni(2+) do not bind to any components of the E3-ligase other than cullin-2, suggesting that cullin-2 is a key target of Co(2+) and Ni(2+). Interestingly, Co(2+) did not affect the complex formation of the ligase, suggesting that the metal binding to cullin-2 affects the function, but not the assembly of the E3-ligase.