Cement-augmented anterior screw fixation of Type II odontoid fractures in elderly patients with osteoporosis

BACKGROUND CONTEXT: Closed reduction and internal fixation by an anterior approach is an established option for operative treatment of displaced Type II odontoid fractures. In elderly patients, however, inadequate screw purchase in osteoporotic bone can result in severe procedure-related complications. PURPOSE: To improve the stability of odontoid fracture screw fixation in the elderly using a new technique that includes injection of polymethylmethacrylat (PMMA) cement into the C2 body. STUDY DESIGN: Retrospective review of hospital and outpatient records as well as radiographs of elderly patients treated in a university hospital department of orthopedic surgery. PATIENT SAMPLE: Twenty-four elderly patients (8 males and 16 females; mean age, 81 years; range, 62-98 years) with Type II fractures of the dens. OUTCOME MEASURES: Complications, cement leakage (symptomatic/asymptomatic), operation time, loss of reduction, pseudarthrosis and revision surgery, patient complaints, return to normal activities, and signs of neurologic complications were all documented. METHODS: After closed reduction and anterior approach to the inferior border of C2, a guide wire is advanced to the tip of the odontoid under biplanar fluoroscopic control. Before the insertion of one cannulated, self-drilling, short thread screws, a 12 gauge Yamshidi cannula is inserted from anterior and 1 to 3 mL of high-viscosity PMMA cement is injected into the anteroinferior portion of the C2 body. During polymerization of the cement, the screws are further inserted using a lag-screw compression technique. The cervical spine then is immobilized with a soft collar for 8 weeks postoperatively. RESULTS: Anatomical reduction of the dens was achieved in all 24 patients. Mean operative time was 64 minutes (40-90 minutes). Early loss of reduction occurred in three patients, but revision surgery was indicated in only one patient 2 days after primary surgery. One patient died within the first eight postoperative weeks, one within 3 months after surgery. In five patients, asymptomatic cement leakage was observed (into the C1-C2 joint in three patients, into the fracture in two). Conventional radiologic follow-up at 2 and 6 months confirmed anatomical healing in 16 of the19 patients with complete follow-up. In two patients, the fractures healed in slight dorsal angulation; one patient developed a asymptomatic pseudarthrosis. All patients were able to resume their pretrauma level of activity. CONCLUSIONS: Cement augmentation of the screw in Type II odontoid fractures in elderly patients is technically feasible in a clinical setting with a low complication rate. This technique may improve screw purchase, especially in the osteoporotic C2 body.

In vitro temperature evaluation during cement augmentation of proximal humerus plate screw tips

BACKGROUND The treatment of proximal humerus fractures in patients with poor bone quality remains a challenge in trauma surgery. Augmentation with polymethylmethacrylate (PMMA) cement is a possible method to strengthen the implant anchorage in osteoporotic bone and to avoid loss of reduction and reduce the cut-out risk. The polymerisation of PMMA during cement setting leads, however, to an exothermic reaction and the development of supraphysiological temperatures may harm the bone and cartilage. This study addresses the issue of heat development during augmentation of subchondrally placed proximal humerus plate screws with PMMA and the possible risk of bone and cartilage necrosis and apoptosis. METHODS Seven fresh frozen humeri from geriatric female donors were instrumented with the proximal humerus interlocking system (PHILOS) plate and placed in a 37°C water bath. Thereafter, four proximal perforated screws were augmented with 0.5 ml PMMA each. During augmentation, the temperatures in the subchondral bone and on the articular surface were recorded with K-type thermocouples. The measured temperatures were compared to threshold values for necrosis and apoptosis of bone and cartilage reported in the literature. RESULTS The heat development was highest around the augmented tips of the perforated screws and diminished with growing distance from the cement cloud. The highest temperature recorded in the subchondral bone reached 43.5°C and the longest exposure time above 42°C was 86s. The highest temperature measured on the articular surface amounted to 38.6°C and the longest exposure time above 38°C was 5 min and 32s. CONCLUSION The study shows that augmentation of the proximal screws of the PHILOS plate with PMMA leads to a locally limited development of supraphysiological temperatures in the cement cloud and closely around it. The critical threshold values for necrosis and apoptosis of cartilage and subchondral bone reported in the literature, however, are not reached. In order to avoid cement extravasation, special care should be taken in detecting perforations or intra-articular cracks in the humeral head.

Cement volume is the most important modifiable predictor for pain relief in BKP: results from SWISSspine, a nationwide registry

Purpose The effectiveness of vertebral augmentation techniques is a currently highly debated issue. The biomechanical literature suggests that cement filling volumes may play an important role in the ‘‘dosage’’ of vertebral augmentation and its pain alleviating effect. Good clinical data about filling volumes are scarce and most patient series are small. Therefore, we investigated the predictors of pain alleviation after balloon kyphoplasty in the nationwide SWISSspine registry where cement volumes are also recorded. Methods All single-level vertebral fractures with no additional fracture stabilization and availability of at least one follow-up within 6 months after surgery were included. The following potential predictors were assessed in a multivariate logistic regression model with the group’s average pain alleviation of 41 points on VAS as the desired outcome: patient age, patient sex, diagnosis, preoperative pain, level of fracture, type of fracture, age of fracture, segmental kyphotic deformity, cement volume, vertebral body filling volume, and cement extrusions. Results There were 194 female and 82 males with an average age of 70.4 and 65.3 years, respectively. Female patients were about twice as likely for achieving the average pain relief compared to males (p = 0.04). The preoperative pain level was the strongest predictor in that the likelihood for achieving an at least 41-point pain relief increased by about 8 % with each additional point of preoperative pain (p\0.001). A thoraco-lumbar fracture had a three times higher odds for the average pain relief compared with a lumbar fracture (p = 0.03). An A.3.1 fracture only had about a third of the probability for average pain relief compared with an A.1.1 fracture (p = 0.004). Cement volumes up to 4.5 ml only had an approximately 40 % chance for a minimum 41-point pain alleviation as compared with cement volumes of at least 4.5 ml (p = 0.007). In addition, the relationship between cement volume and pain alleviation followed a dose-dependent pattern. Conclusions Cement volume was revealed as a significant predictor for pain relief in BKP. Cement volume was the third most important influential covariate and the most important modifiable and operator dependent one. The clear dose-outcome relationship between cement filling volumes and pain relief additionally supports these findings. Cement volumes of [4.5 ml seem to be recommendable for achieving relevant pain alleviation. Patient sex and fracture type and location were further significant predictors and all these covariates should be recorded and reported in future studies about the pain alleviating effectiveness of vertebral augmentation procedures.

Glass ionomer cement in otological microsurgery: experience over 16 years

A retrospective evaluation of glass ionomer cement (GIC) in middle ear surgery with emphasis on short- and long-term safety was conducted at the tertiary referral center. GIC was applied between 1995 and 2006 in 444 patients in otologic surgery. Technical aspects, safety, benefits and complications due to GIC were analysed until 2011 (follow-up 5-16 years; mean 10 years). GIC was applied in stapes surgery (228 primary, 92 revisions), cochlear implants (108) and implantable hearing aids (7), ossiculoplasty (7), for coverage of opened mastoid air cells towards the external ear canal (1) and inner ear fistula closure (1). GIC turned out to be very handy in stapes surgery for optimal prosthesis fixation at the incus (260) and on the malleus handle (60) without complications. Results suggest that GIC may diminish the danger of incus necrosis in primary stapedotomy. In cochlear implants and implantable hearing aids, GIC was used for casing alone (74), casing and electrode fixation (27) and electrode alone fixation (14). Inflammatory reactions were observed in five cases (4.3 %), mostly after trauma. Broken cement fragments appeared to promote foreign body rejection. In seven cases an incudo-stapedial gap was repaired with GIC with excellent hearing gain; in three cases (43 %) revision surgery was needed due to cement breakage. In one case, GIC was applied for a watertight coverage of opened mastoid cells, and in the other for fistula closure of the lateral semi-circular canal over cartilage, covered with bone pathé; follow-up was uneventful. Targeted use of GIC in middle ear surgery rarely poses problems. GIC cannot be used in neuro-otosurgery in contact with cerebrospinal fluid because of possible aluminium encephalopathy.

Encapsulation of caesium-loaded Ionsiv in cement

The microporous material Ionsiv is used for 137Cs removal from aqueous nuclear waste streams. In the UK, Cs-loaded Ionsiv is classed as an intermediate-level waste; no sentencing and disposal route is yet defined for this material and it is currently held in safe interim storage on several nuclear sites. In this study, the suitability of fly ash and blast furnace slag blended cements for encapsulation of Cs-Ionsiv in a monolithic wasteform was investigated. No evidence of reaction or dissolution of the Cs-Ionsiv in the cementitious environment was found by scanning electron microscopy and X-ray diffraction. However, a small fraction (<= 1.6 wt.%) of the Cs inventory was released from the encapsulated Ionsiv during leaching experiments carried out on hydrated samples. Furthermore, it was evident that K and Na present in the cementitious pore water exchanged with Cs and H in the Ionsiv. Therefore, cement systems lower in K and Na, such as slag based cements, showed lower Cs release than the fly ash based cements.

Reduction of cement leakage by sequential PMMA application in a vertebroplasty model

PURPOSE Leakage is the most common complication of percutaneous cement augmentation of the spine. The viscosity of the polymethylmethacrylate (PMMA) cement is strongly correlated with the likelihood of cement leakage. We hypothesized that cement leakage can be reduced by sequential cement injection in a vertebroplasty model. METHODS A standardized vertebral body substitute model, consisting of aluminum oxide foams coated by acrylic cement with a preformed leakage path, simulating a ventral vein, was developed. Three injection techniques of 6 ml PMMA were assessed: injection in one single step (all-in-one), injection of 1 ml at the first and 5 ml at the second step with 1 min latency in-between (two-step), and sequential injection of 0.5 ml with 1-min latency between the sequences (sequential). Standard PMMA vertebroplasty cement was used; each injection type was tested on ten vertebral body substitute models with two possible leakage paths per model. Leakage was assessed by radiographs using a zonal graduation: intraspongious = no leakage and extracortical = leakage. RESULTS The leakage rate was significantly lower in the "sequential" technique (2/20 leakages) followed by "two-step" (15/20) and "all-in-one" (20/20) techniques (p < 0.001). The RR for a cement leakage was 10.0 times higher in the "all-in-one" compared to the "sequential" group (95 % confidence intervals 2.7-37.2; p < 0.001). CONCLUSIONS The sequential cement injection is a simple approach to minimize the risk for leakage. Taking advantage of the temperature gradient between body and room temperature, it is possible to increase the cement viscosity inside the vertebra while keeping it low in the syringe. Using sequential injection of small cement volumes, further leakage paths are blocked before further injection of the low-viscosity cement.

Stability of Cs-Ionsiv in Portland cement blends for radioactive waste disposal

The suitability of Portland cement blends for encapsulation of Cs-Ionsiv in a monolithic wasteform was investigated. No evidence of reaction or dissolution of the Cs-Ionsiv in the cementitious environment was found by scanning electron microscopy and X-ray diffraction. However, a small fraction (≤1.6 wt%) of the Cs inventory was released from the encapsulated Ionsiv during leaching experiments carried out on hydrated samples. Cs release was enhanced by exchange of K and Na present in the cementitious pore water. Cement systems lower in K and Na, such as slag based blends, showed lower Cs release than the fly ash based analogues. © 2010 Materials Research Society.

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.

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.