Introduction : Closed reduction is widely accepted as the initial management of subaxial facet dislocation. However, there is a substantial risk of neurological deterioration due to herniated discs or fractured vertebral bodies during the procedure. Recently, it has been reported that open reduction and fixation via an anterior approach for subaxial facet dislocation had good outcomes. However, some cases with locked facets were difficult to reduce successfully through the anterior approach. To date, there is no established treatment strategy for the fixation of subaxial facet dislocations. We present two cases of subaxial facet dislocation that were treated with open reduction using a combination of distraction using a vertebral spreader and manual traction with the Sugita head frame through an anterior approach, followed by combined anterior-posterior fixation.

  Case presentation : Case 1 : A 73-year-old woman was admitted for numbness and paralysis of the left upper limb after a traffic accident. Computed tomography (CT) and magnetic resonance imaging revealed moderate spinal cord compression due to C6-7 facet dislocation with C6-7 left locked facet and C6-7 left intervertebral foramen stenosis.

  Case 2 : A 69-year-old man was admitted for numbness and paralysis of both upper and right lower limbs after falling down stairs. CT revealed mild spinal cord compression due to C6-7 facet dislocation with a C6-7 right locked facet.

  Both patients underwent open reduction and fixation via an anterior approach followed by posterior fixation and exhibited no neurological deterioration after surgery. There were no implant failures or cervical deformities one year after the operation in either case.

  Conclusions : The reduction technique using a combination of a vertebral spreader and manual traction was beneficial for facilitating successful reduction through an anterior approach for subaxial facet dislocation with locked facets. Combined anterior-posterior fixation in the acute phase was useful for subaxial facet dislocation because rigid stabilization could lead to early rehabilitation.

  Introduction : Condoliase injection for lumbar disc herniation is less invasive than surgical treatment and has been widely used in recent years. We encountered a case in which a herniated disc worsened after treatment with condoliase (Hernicore^®) injection. Thereafter discectomy was performed. We also report the pathology of the disc removed immediately after condoliase injection.

  Case presentation : A 34-year-old man with a history of lumbago and left lower extremity pain for 6 months presented to another hospital, wherein magnetic resonance imaging (MRI) showed subligamentous extruded type L5-S1 disc herniation. The patient underwent condoliase injection 3 months after the first visit. However, the patient’s symptoms worsened on the second day after condoliase therapy and did not improve despite the nerve block. MRI showed a transligamentous extrusion-type hernia and substantial compression of the dural sac.

  Course of treatment : After admission to our hospital, although the patient was administered pregabalin and tramadol, there was no improvement : his preoperative Japanese Orthopaedic Association (JOA) lumbago score was 9/29. Seventeen days after condoliase injection, discectomy was performed to remove the sequestrated herniation. The ventral side of the dural sac was strongly adhered to the disc space. Postoperatively, the patient’s left lower extremity pain improved. However, his lumbago persisted, with a postoperative JOA lumbago score of 15/29. Postoperative MRI revealed Modic type 1 changes in the L5/S1 intervertebral space. His lumbago improved 2 months after surgery, and the Modic type 1 changes disappeared 5 months after surgery.

  Pathological findings : We compared the excised herniated disc with four aged-matched surgical control cases without condoliase treatment. Toluidine blue staining showed that glycosaminoglycans were substantially decreased in the condoliase-treated discs compared with the control discs. No histological changes in structure were observed.

  Discussion : In clinical trials, surgery was still required in approximately 10% of cases after condoliase treatment. However, early deterioration after treatment is rare. The pathological findings in the present case indicated that the glycosaminoglycans in the intervertebral disc were degraded early after condoliase administration. Due to the prolonged postoperative lumbago, we considered the possibility of condoliase-induced tissue damage in addition to bacterial discitis.

  The symptoms of mononeuritis associated with eosinophilic granulomatosis with polyangiitis (EGPA) resemble those of radiculopathy associated with spinal diseases. Herein, we report three cases of neuropathy caused by EGPA, which were suspected of spinal diseases.

  Case 1 : A 71-year-old woman had a chief complaint of back pain and numbness in both lower limbs. Imaging examination showed L4 and L5 spondylolysis and nerve root stenosis of the intervertebral foramen, and posterior lumbar interbody fusion (PLIF) was scheduled. However, preoperative blood test results revealed a white blood cell count of 37,800 (eosinophils : 76%). The patient was referred to the Department of Neurology at another hospital, where she was diagnosed with EGPA and treated with steroid pulse therapy.

  Case 2 : A 38-year-old woman presented with a chief complaint of numbness and pain in the right upper extremity and weakness in the right lower extremity. Cervical spine magnetic resonance imaging (MRI) showed mild intervertebral foramen stenosis. She was placed under observation with medication. However, her right lower extremity weakness rapidly progressed. Since Guillain-Barré syndrome was suspected, the patient was referred to the Department of Neurology for further management. A blood test revealed 30,500 white blood cells (eosinophils : 80%), which led to the diagnosis of EGPA.

  Case 3 : A 56-year-old man had a chief complaint of pain in both perineal regions and numbness in the right forearm. Lumbar MRI revealed a suspected arachnoid cyst. A blood test showed 31,000 white blood cells (eosinophils : 74.6%). Therefore, the patient was referred to the Department of Collagen Disease due to suspicion of EGPA.

  All three patients had a history of bronchial asthma.

  EGPA is a type of anti-neutrophil cytoplasmic antibody (ANCA) -associated vasculitis formerly called Churg-Strauss syndrome. Symptoms are preceded by asthma and allergic rhinitis and followed by polyangiitis mononeuritis with a high frequency of numbness, pain, and weakness in the extremities. Patients are often referred to spine surgeons on suspicion of spinal disease. However, focusing solely on imaging findings may delay patient's opportunity for early treatment and result in residual neurological deficits. Since early diagnosis and treatment are important, EGPA is one of the important diseases that spine surgeons should be aware of.

  Intradural extramedullary metastases of renal cell carcinoma are rare. We report a case of intradural extramedullary spinal cord metastasis and intramedullary invasion of renal cell carcinoma after treatment for brain and lung metastases following initial removal.

  A 43-year-old woman presented with a history of right renal cell carcinoma. She developed sudden disturbances in consciousness and dizziness and was transferred to our hospital at the age of 40 years. The cerebellar metastasis presented with cerebellar hemorrhage. We removed the left cerebellar hemorrhage, which led to the diagnosis of brain metastasis from renal cell carcinoma. The patient underwent cranial radiotherapy and chemotherapy. Three years later, thoracic magnetic resonance imaging (MRI) revealed T2 dorsal and T2-3 ventral intradural extramedullary tumors. The tumor had grown within 6 months, and the patient complained of chest and back pain. She also had bilateral lower-limb paralysis, bilateral lower-limb sensory deficits, and bladder and bowel dysfunctions. Tumor embolization and partial removal of thoracic spinal cord tumors were performed. Intraoperative findings revealed an indistinct boundary between the ventral spinal tumor and spinal cord. We diagnosed the patient with intradural extramedullary metastasis of renal cell carcinoma and medullary invasion of the extramedullary tumor. The patient underwent postoperative spinal radiotherapy and chemotherapy. Neurological symptoms improved postoperatively and were maintained for 18 months postoperatively.

  Despite the poor prognosis of renal cell carcinoma and its metastasis to the spinal cord, palliative surgery and adjuvant therapy may maintain the quality of life and activities of daily living in patients.