86 Many of the complications reported with vertebroplasty/ kyphoplasty are directly related to the use of PMMA. Leakage of cement into the venous system has been reported and may lead to pulmonary embolism, pulmonary cement embolism, or cerebral vascular cement embolism [1, 2, 4–6]. Neurological damage has also been reported. Acute paraplegia from cement leakage compressing the spinal cord has been reported [1, 2, 4, 5]. In addition, the modulus of elasticity of PMMA in the treated level causesa mismatch between it and the adjacent untreated levels. The transition zone between treated and unreated levels causes a so-called stress-riser effect, which has been through to result in an increased incidence of adjacent level com- pression fractures [9, 10]. Reports of adjacent fractures for vertebroplasty have been reported to be between 12% and 52%, and between 3% and 29% for kyphoplasty [1, 6, 9]. Foreign-body reactions to PMMA have also been reported [5]. Another criticism of the use of PMMA in close proximity to the spinal cord is the heat released during the exothermic reaction with cement curing [2, 5]. Although there is experimental evidence in animal models to show the potential for neural tissue damage due to heat, there has not been a reported case of this complication in humans at the time of this writing [2, 5]. It should be noted that reports of poor outcome for both vertebroplasty and kyphoplasty ﬂuctuate greatly. The material and biological characteristics of morcel- ized bone are among the major reasons for the perceived advantages of Optimesh. Compressed allograft bone can be expected to more closely mimic the physical properties of the surrounding native bone [1, 2]. If the stiffness of ver- tebral bodies inﬁltrated with PMMA is in fact the cause of an increased risk of subsequent VCF, the use of bone as graft material may be useful in adjacent vertebrae fracture risk reduction. Due to the porous nature of the woven mesh bag and the morselized bone, it is conceivable that revas- cularization may occur through and around the graft [2]. Proposed clinical indications The criteria for the application of Optimesh for PVA have been described previously [1]. The major indication is VCFs with pain [1, 2]. Although it is not currently approved for interbody use, it has been anecdotally used to effect interbody fusion for the treatment of degenerative disk disease [13]. The complete list of indications and contraindications described by Chiu and Stechison [1] is as follows: Indications 1. Management of painful osteoporotic or posttraumatic VCFs. Curr Rev Musculoskelet Med (2008) 1:84–87 2. Intractable, focal band-like radicular pain that is worse with weight bearing and is relieved with rest or in a recumbent position. 3. Pain refractory to analgesics and narcotics. 4. Osteoporosis, aggressive hemangioma, metastatic disease, osteogenic imperfecta, trauma, or vertebral osteonecrosis resulting in a painful compression fracture. 5. For the management of chronic nonunion following traumatic vertebral body fractures 6. Internal stabilization of unstable posttraumatic VCFs. 7. Management of multiple compression fractures in a patient with poor pulmonary reserve. Absolute contraindications 1. Patients with painless asymptomatic stable VCFs. 2. Massive ‘‘burst’’ osteoporotic or nonosteoporotic fractures. 3. Patients with fracture(s) that are clearly responding to medical therapy. 4. Osteomyelitis of target vertebra. 5. Prophylactic treatment with no evidence of fracture. 6. Uncorrected coagulation/bleeding disorder. Relative contraindications 1. Medically high-risk or unstable patient. 2. Patients with retropulsed bone causing spinal canal compromise of greater than 20%. 3. Restless patient (unable to lie prone for the entire procedure under IV conscious sedation). 4. Patient with pain due to herniated spinal disk, facet arthropathy, spinal stenosis, or other degenerative condition. 5. Pathological fracture with tumor signiﬁcantly extend- ing into the spinal canal [1]. Clinical outcomes Optimesh has been recently approved for use. So far, no large clinical trials have been reported to date. However, several successful cases have been reported. Chiu and Stechison reported three successful procedures leading to almost immediate postoperative pain reduction [1]. All three patients were of age greater than 70 years, had fractures at different levels, and received conscious seda- tion and local anesthesia [1]. A CT scan performed seven weeks post-operatively suggested osteointegration at the vertebral body-graft interface in one patient [1]. Modiﬁcations to the procedures in kyphoplasty and vertebroplasty may reduce the problems associated with the use of PMMA. The use of calcium phosphate as a graft material has been demonstrated to be osteoconductive [14].