Background Context. Different minimally invasive approaches to the lumbar spine have been proposed but they can be associated with increased risk of complications, steep learning curve and longer operative time. Purpose. To report the complications associated with a minimally invasive technique of retroperitoneal anterolateral approach to the lumbar spine. Study design. Retrospective study of 179 patients who underwent anterior oblique lumbar interbody fusion (OLIF). Methods. A total of 179 patients with previous posterior instrumented fusion undergoing OLIF were included. This muscle-splitting approach consists in anterolateral exposure through a 4 cm incision followed by placement of a PEEK cage filled with bone graft and/or substitute. Results. Patients were aged 54.110.6 years with BMI of 24.84.1 kg/m2. Length of follow-up was (0.90.7 years), including 17 patients with a minimum follow-up of 2 years. A left-sided approach was done in 174 patients. The procedure was performed at L1–2 in 4, L2–3 in 54, L3–4 in 120, L4–5 in 134 and L5-S1 in 6 patients. It was done at 1 level in 56, 2 levels in 107, and 3 levels in 16 patients. Operative time and blood loss were respectively 32.513.2 min and 57131 cc per level fused. There were 19 patients with single complication and one with two complications, including two patients with postoperative radiculopathy after L3–5 OLIF. There was no abdominal weakness or herniation. Conclusion. Minimally invasive OLIF can be performed easily and safely from L2 to L5, and at L1–2 and L5-S1 for selected cases. Up to 3 levels can be addressed through a “sliding window”. It is associated with minimal blood loss and short operative time. The risk of complications is similar to that reported for traditional anterior approaches, with the advantage of decreasing the risk of abdominal wall weakness or herniation

Objectives. The aim of this systematic literature review was to assess the clinical level of evidence of commercially available demineralised bone matrix (DBM) products for their use in trauma and orthopaedic related surgery. Methods. A total of 17 DBM products were used as search terms in two available databases: Embase and PubMed according to the Preferred Reporting Items for Systematic Reviews and Meta Analyses statement. All articles that reported the clinical use of a DBM-product in trauma and orthopaedic related surgery were included. Results. The literature search resulted in 823 manuscripts of which 64 manuscripts met the final inclusion criteria. The included manuscripts consisted of four randomised controlled trials (level I), eight cohort studies (level III) and 49 case-series (level IV). No clinical studies were found for ten DBM products, and most DBM products were only used in combination with other grafting materials. DBM products were most extensively investigated in spinal surgery, showing limited level I evidence that supports the use Grafton DBM (Osteotech, Eatontown, New Jersey) as a bone graft extender in posterolateral lumbar fusion surgery. DBM products are not thoroughly investigated in trauma surgery, showing mainly level IV evidence that supports the use of Allomatrix (Wright Medical, London, United Kingdom), DBX (DePuy Synthes, Zuchwil, Switzerland), Grafton DBM, or OrthoBlast (Citagenix Laval, Canada) as bone graft extenders. Conclusions. The clinical level of evidence that supports the use of DBM in trauma and orthopaedic surgery is limited and consists mainly of poor quality and retrospective case-series. More prospective, randomised controlled trials are needed to understand the clinical effect and impact of DBM in trauma and orthopaedic surgery. Cite this article: J. van der Stok, K. A. Hartholt, D. A. L. Schoenmakers, J. J. C. Arts. The available evidence on demineralised bone matrix in trauma and orthopaedic surgery: A systemati c review. Bone Joint Res 2017;6:423–432. DOI: 10.1302/2046-3758.67.BJR-2017-0027.R1

Heterotopic ossification occurring after the use of commercially available bone morphogenetic proteins has not been widely reported. We describe four cases of heterotopic ossification in patients treated with either recombinant bone morphogenetic protein 2 or recombinant bone morphogenetic protein 7. We found that while some patients were asymptomatic, heterotopic ossification which had occurred around a joint often required operative excision with good results.