Avascular necrosis of the femoral head after surgery for lumbar spinal stenosis

[Potential complications of patient positioning in spine surgery]

Patient position on the operating table during spine surgery is important for optimal intraoperative manipulations. However, this position is far from physiological one. An unnatural position, surgery time and sometimes necessary intraoperative change in body position can lead to certain neurological and somatic complications. Most of these events can significantly reduce the patient's working capacity and quality of life and even result disability. Medical staff placing the patient on operating table, neurosurgeons and anesthesiologists should be aware of risk factors of similar complications and their prevention. The authors describe the most serious and difficult for correction conditions, such as peripheral neuropathy, damage to visual analyzer, as well as optimal method of patient positioning.

Complications associated with prone positioning in elective spinal surgery

Complications associated with prone surgical positioning during elective spine surgery have the potential to cause serious patient morbidity. Although many of these complications remain uncommon, the range of possible morbidities is wide and includes multiple organ systems. Perioperative visual loss (POVL) is a well described, but uncommon complication that may occur due to ischemia to the optic nerve, retina, or cerebral cortex. Closed-angle glaucoma and amaurosis have been reported as additional etiologies for vision loss following spinal surgery. Peripheral nerve injuries, such as those caused by prolonged traction to the brachial plexus, are more commonly encountered postoperative events. Myocutaneous complications including pressure ulcers and compartment syndrome may also occur after prone positioning, albeit rarely. Other uncommon positioning complications such as tongue swelling resulting in airway compromise, femoral artery ischemia, and avascular necrosis of the femoral head have also been reported. Many of these are well-understood and largely avoidable through thoughtful attention to detail. Other complications, such as POVL, remain incompletely understood and thus more difficult to predict or prevent. Here, the current literature on the complications of prone positioning for spine surgery is reviewed to increase awareness of the spectrum of potential complications and to inform spine surgeons of strategies to minimize the risk of prone patient morbidity.

Osteonecrosis of the Femoral Head in the Setting of a Complex Acetabulum Fracture without Hip Dislocation Treated Surgically Using Ilio-inguinal Approach: A Case Report

Osteonecrosis in isolated fractures of the acetabulum without dislocation of hip seems to be a known complication, but to our knowledge it has not been reported adequately. The causative nature of post-traumatic femoral head osteonecrosis has not been studied critically. The pathophysiology of osteonecrosis in this case also eludes us. Striking evidence points towards the intra-operative blood loss and low mean arterial pressure possibly leading to hypo-perfusion of femoral head leading to osteonecrosis. Fractures of the acetabulum pose a difficult problem for the patient and the surgeon because of possible complications. Thus any surgeon involved in surgery for fractures of the acetabulum should be aware of the possibility of this potential complication. Here is a 61-year male, who sustained a complex fracture of the acetabulum without hip dislocation, subsequently was treated surgically with internal fixation using an anterior approach, 10 months after surgery patient developed osteonecrosis of the femoral head.

Anaesthesia in the prone position

Prone positioning of patients during anaesthesia is required to provide operative access for a wide variety of surgical procedures. It is associated with predictable changes in physiology but also with a number of complications, and safe use of the prone position requires an understanding of both issues. We have reviewed the development of the prone position and its variants and the physiological changes which occur on prone positioning. The complications associated with this position and the published techniques for various practical procedures in this position will be discussed. The aim of this review is to identify the risks associated with prone positioning and how these risks may be anticipated and minimized.

Osteonecrosis: death of bone cells

Osteonecrosis is a pathologic process resulting from direct and indirect injury to the bones' vascular supply. Varying microangiopathic entities cause the death of bone. Bone cell death subsequently causes loss of joint function, impaired mobility, and microfractures leading to collapse of the joints' articular surface. The pathogenesis of osteonecrosis is presented.