The most important parameters to analyse the cervical sagittal balance according to the literature available today for good clinical outcomes are the following: C7 or T1 slope, average value 20°, must not be higher than 40°. cSVA must not be less than 40°C (mean value 20 mm). SCA (spine cranial angle) must stay in a norm (83° ± 9°). Future studies should focus on those three parameters to analyse and compare pre and post op data and to correlate the results with the quality of life improvement.

Avascular necrosis of the femoral head is caused by a multitude of etiologic factors and is associated with collapse with a risk of hip arthroplasty in younger populations. A focus on early disease management with the use of stem cells was proposed as early as 1985 by the senior author (PH). We undertook a systematic review of the medical literature to examine the progress in cell therapy during the last 30 years for the treatment of early stage osteonecrosis.

Background Surgical treatment of thoracic disc herniation (TDH) is technically demanding due to its proximity to the spinal cord. Methods Literature review. Results Symptomatic TDH is a rare condition predominantly localized between T8 and L1. Surgical indications include intractable back or radicular pain, neurological deficits, and myelopathy signs. Giant calcified TDH (> 40% spinal canal occupation) are frequently associated with myelopathy, intradural extension, and post-operative complications. Careful pre-operative planning helps reduce the risk of complications. Pre-operative CT and MRI identify the hernia's location and size, calcifications, and intradural extension. The approach must provide adequate dural sac visualization with minimal manipulation of the cord. Nonanterior approaches are favoured if they provide at least equal exposure than anterior approach owing to higher risk of pulmonary morbidity associated with anterior approach. A transthoracic approach is recommended for central calcified herniated discs. A posterolateral approach is often suitable for non-calcified lateralized TDH. Thoracoscopic approaches are less invasive but have a substantial learning curve. Retropleural mini-thoracotomy is an acceptable alternative. Pre-operative identification of the pathological level is confirmed by intra-operative level check. Intra-operative cord monitoring is preferable but warrant further studies. Magnification and adequate lightening of the surgical field are paramount (microscope, thoracoscopy). Intra-operative CT scan with navigation is becoming increasingly popular since it provides real-time control on the decompression. Indications of fusion consist of pre-operative back pain, Scheuermann's disease, multilevel resection, wide vertebral body resection (> 50%), and herniation at thoracolumbar junction. Neurological deterioration, dural tear, and subarachnoid-pleural fistula are the most severe complications. Conclusion Further improvements are still warranted in thoracic spine surgery despite the advent of minimally invasive techniques. Intra-operative CT scan will probably enhance the safety of the TDH surgery.

Thoracic disc herniation is rare and mainly occurs between T8 and L1. The herniation is calcified in 40% of cases and is labeled as giant when it occupies more than 40% of the spinal canal. A surgical procedure is indicated when the patient has severe back pain, stubborn intercostal neuralgia or neurological deficits. Selection of the surgical approach is essential. Mid-line calcified hernias are approached from a transthoracic incision, while lateralized soft hernias can be approached from a posterolateral incision. The complication rate for transthoracic approaches is higher than that of posterolateral approaches; however, the former are performed in more complex herniation cases. The thoracoscopic approach is less invasive but has a lengthy learning curve. Retropleural mini-thoracotomy is a potential compromise solution. Fusion is recommended in cases of multilevel herniation, herniation in the context of Scheuermann's disease, when more than 50% bone is resected from the vertebral body, in patients with preoperative back pain or herniation at the thoracolumbar junction. Along with complications specific to the surgical approach, the surgical risks are neurological worsening, dural breach and subarachnoid-pleural fistulas. Giant calcified herniated discs are the largest contributor to myelopathy, intradural extension and postoperative complications. Some of the technical means that can be used to prevent complications are explored, along with how to address these complications.