Percutaneous cement augmentation for the treatment of depression fractures of the tibial plateau

The management of insufficiency fractures of the tibial plateau in osteoporotic patients can be very challenging, since it is difficult to achieve a stable fixation, an essential condition for the patients' early mobilization. We present a minimally invasive technique for the treatment of proximal tibial plateau fractures, "tibiaplasty", using percutaneous polymethylmethacrylate augmentation. Five osteoporotic patients (7 fractures) with a non-traumatic insufficiency tibial plateau fracture were treated with this technique at the authors' institution from 2006 to 2008. The patients' median age was 79 (range 62-88) years. The intervention was performed percutaneously under general or spinal anesthesia; after the intervention, immediate full weight bearing was allowed. The technique was feasible in all patients and no complications related to the intervention were observed. All patients reported a relevant reduction in pain, were able to mobilize with full weight bearing and would undergo the operation again. No secondary loss of reduction or progression of arthrosis was observed in radiological controls; no revision surgery was required. Our initial results indicate that tibiaplasty is a good treatment option for the management of insufficiency in tibial plateau fractures in osteoporotic patients. The technique is minimally invasive, safe and allows immediate mobilization without restrictions. In our group of patients, we found excellent early to mid-term results.

Automated cement segmentation in vertebroplasty

Vertebroplasty is a minimally invasive procedure with many benefits; however, the procedure is not without risks and potential complications, of which leakage of the cement out of the vertebral body and into the surrounding tissues is one of the most serious. Cement can leak into the spinal canal, venous system, soft tissues, lungs and intradiscal space, causing serious neurological complications, tissue necrosis or pulmonary embolism. We present a method for automatic segmentation and tracking of bone cement during vertebroplasty procedures, as a first step towards developing a warning system to avoid cement leakage outside the vertebral body. We show that by using active contours based on level sets the shape of the injected cement can be accurately detected. The model has been improved for segmentation as proposed in our previous work by including a term that restricts the level set function to the vertebral body. The method has been applied to a set of real intra-operative X-ray images and the results show that the algorithm can successfully detect different shapes with blurred and not well-defined boundaries, where the classical active contours segmentation is not applicable. The method has been positively evaluated by physicians.

Complications related to cement leakage in sacroplasty

Data concerning the safety of sacroplasty in terms of cement leakage is scarce. Frequency, distribution patterns and clinical consequences of cement leakage were assessed in 33 patients (28 female, mean age: 74 +/- 10 yrs; bilateral SIF: n = 30, 63 sacroplasties) treated with sacroplasty between 06/2003 and 11/2010 in a retrospective study using patients' records, operative notes and postoperative radiographs. Cement leakage was noted within the fracture gap (27%), into veins (6%), neuroforamina (3%) or in the intervertebral disc space L5/S1 (2%). In one patient, cement leakage into the fracture gap led to unilateral radiculopathy of the 5th lumbar nerve root. Leakage into the fracture gap is at high risk of affecting the 5th lumbar nerve root due to the special course of its ventral branch over the sacral promontory. The risks of cement leakage with neurological impairment should be explained to patients.

The effect of standard and low-modulus cement augmentation on the stiffness, strength, and endplate pressure distribution in vertebroplasty

Vertebroplasty restores stiffness and strength of fractured vertebral bodies, but alters their stress transfer. This unwanted effect may be reduced by using more compliant cements. However, systematic experimental comparison of structural properties between standard and low-modulus augmentation needs to be done. This study investigated how standard and low-modulus cement augmentation affects apparent stiffness, strength, and endplate pressure distribution of vertebral body sections.

Intra-articular calcium phosphate cement: Its fate and impact on joint tissues in a rabbit model

Clinical application of injectable ceramic cement in comminuted fractures revealed penetration of the viscous paste into the joint space. Not much is known on the fate of this cement and its influence on articular tissues. The purpose of this experimental study was to assess these unknown alterations of joint tissues after intra-articular injection of cement in a rabbit knee. Observation periods were from 1 week up to 24 months, with three rabbits per group. Norian SRS cement was injected into one knee joint, the contralateral side receiving the same volume of Ringers' solution. Light microscopic evaluation of histologic sections was performed, investigating the appearance of the cement, inflammatory reactions, and degenerative changes of the articular surface. No signs of pronounced acute or chronic inflammation were visible. The injected cement was mainly found as a single particle, anterior to the cruciate ligaments. It became surrounded by synovial tissues within 4 weeks and showed signs of superficial resorption. In some specimens, bone formation was seen around the cement. Degeneration of the articular surface showed no differences between experimental and control side, and no changes over time became apparent. No major degenerative changes were induced by the injected cement. The prolonged presence of cement still seems to make it advisable to remove radiologically visible amounts from the joint space.

Evaluation of hydroxyapatite cement for frontal sinus obliteration after mucocele resection

OBJECTIVES: To retrospectively evaluate our experience with frontal sinus obliteration using hydroxyapatite cement (BoneSource; Stryker Biotech Europe, Montreux, Switzerland) and compare it with fat obliteration over the approximate same period. Frontal sinus obliteration with hydroxyapatite cement represents a new technique for obliteration of the frontal sinus after mucocele resection. METHODS: Exploration of the frontal sinus was performed using bicoronal, osteoplastic flaps, with mucosal removal and duct obliteration with tissue glue and muscle or fascia. Flaps were elevated over the periorbita, and Silastic sheeting was used to protect the BoneSource material from exposure as it dried. The frontal table was replaced when appropriate. RESULTS: Sixteen patients underwent frontal sinus obliteration with fat (fat obliteration group), and 38 patients underwent obliteration with BoneSource (BoneSource group). Fat obliteration failed in 2 patients, who underwent subsequent BoneSource obliteration, and none of the patients in the BoneSource group has required removal of material because of recurrent complications. Frontobasal trauma (26 patients [68%] in the BoneSource group and 9 patients [56%] in the fat obliteration group) was the most common history of mucocele formation in both groups. Major complications in the BoneSource group included 1 patient with skin fistula, which was managed conservatively, and 1 patient with recurrent ethmoiditis, which was managed surgically. Both complications were not directly attributed to the use of BoneSource. Contour deficit of the frontal bone occurred in 1 patient in the fat obliteration group and in none in the BoneSource group. Two patients in the fat obliteration group had donor site complications (hematoma and infection). Thirteen patients in the BoneSource group had at least 1 prior attempt at mucocele drainage, and no statistical relation existed between recurrent surgery and preservation of the anterior table. CONCLUSION: Hydroxyapatite is a safe, effective material to obliterate frontal sinuses infected with mucoceles, with minimal morbidity and excellent postoperative contour.