Inter- and intra-batch variability in the handling characteristics and viscosity of commonly used antibiotic-loaded bone cements

BACKGROUND

Several factors can affect the viscosity of a cement and therefore its handling characteristics. We performed an in vitro study to ascertain whether anecdotal observations of differences in handling between batches of the same brand of cement actually existed.

METHODS

3 batches of Simplex P Tobramycin (SPT), Refobacin Bone Cement (RBC), SmartSet GHV (SSG) and Palacos R+G (PRG) were tested. 6 replicates of each batch were vacuum-mixed and their viscosity in relation to time was measured under laboratory conditions using a rheometer. We examined the handling characteristics of 6 replicates of each batch after they were hand-mixed under theater conditions.

RESULTS

Inter- and intra-batch variability was seen in the viscosity of all brands of cement tested. Interbatch calculations were influenced by high intra-batch variability in viscosity. The viscosity of RBC cement was similar to that of SSG, but different to that of PRG (p = 0.01 at 5 N and p = 0.009 at 40 N).

INTERPRETATION

Our results suggest that in clinical practice, extrinsic factors such as preparation conditions and methods probably play a more important role than the intrinsic variability of cements. However, variability in handling and viscosity will exist in all brands of cement prepared under theater conditions and the surgeon must be aware of why they may act differently.

In vitro comparison of Refobacin-Palacos R with Refobacin Bone Cement and Palacos R + G

BACKGROUND

Refobacin Palacos R (RPR) is no longer produced and Palacos R + G (PRG) and Refobacin Bone Cement R (RBC) have been introduced to supersede it. We performed an in vitro study to ascertain whether the handling and mechanical properties of the more recent cement preparations are different to those of their predecessor.

METHODS

The 3 cements were tested to ISO 5833 and German DIN 53435 standards. In addition, their gentamicin elution, shrinkage, viscosity, and handling characteristics were studied.

RESULTS

All 3 cements had comparable mechanical properties exceeding the ISO 5833 and DIN 53435 standards. They eluted similar amounts of gentamicin and had comparable shrinkage. In the batches tested, RBC showed statistically significantly longer handling curves. Both PRG and RBC had statistically significantly lower viscosities as they cured compared to their predecessor.

INTERPRETATION

Surgeons must be aware that both successor cements do not appear to have handling curves and viscoelastic properties identical to those of RPR.

[Application of gentamycini impregnated polymethylmethacrylate (PMMA) (Septopal) in treatment of infected nonunion. Own experiments]

INTRODUCTION

Treatment techniques of osteomyelitis and infected nonunion require local antibiotic-therapy in the infection places because of the necessity of achievement of a very high concentration of antibiotic. Among the methods of local application of antibiotic we have the possibility of non-absorbale carriers application where polymethylmethacrylate (PMMA) is the carrier. Aminoglycosides are the most commonly employed antibiotics for use with PMMA.

PURPOSE OF THE WORK

Estimation of the possibility of use gentamycini-impregnated polymethylmethacrylate (PMMA) (Septopal) in treatment of infected nonunion.

MATERIAL AND METHODS

In the years 2001-2006 in Clinic of Traumatology and Hand Surgery in Wrocław Medical University, 16 patients were treated because of osteomyelitis and infected nonunion of the long bone. Osteomeylitis, according to the Cierny-Mader's classification, was determined as type IVA in 8 patients, as type IIIA in 4 patients, as type IVB in 4 patients. In stage I surgical cleaning focus of the infected nonunion, external stabilization and implantation of PMMA with gentamycyni were performed, in stage II bone graft with length from 2 to 5 cm was applied.

RESULTS

Eradication of the inflammatory process was achieved 13 patients, bone union-in 12 patients. The mean time of bone union achievement was 9 months. The failures concerned mainly patients with type IVB of osteomyelitis according to Cierny-Mader's classification.

CONCLUSIONS

Application of PMMA with gentamycini is an efficient method in the treatment of traumatic osteomyelitis. The reults of osteomyelitis treatment correspond to the osteomyelitis classification according to Cierny-Mader. Application of PMMA with gentamycyni in connection with surgery of nonunion prevents possible infection and creates the space for bone grafts.

[Sacroplasty for the treatment of sacral insufficiency fractures]

Sacral insufficiency fractures are an easily overlooked injury of the elderly, leading to severe and debilitating low back pain. Percutaneous vertebroplasty with polymethylmethacrylate (PMMA) has become the treatment of choice for painful osteoporotic vertebral compression fractures. This is mainly due to the excellent results in pain relief, combined with a low morbidity of the procedure and the possibility of performing it in an outpatient setting. This well-known technique can be transferred to the treatment of sacral insufficiency fractures for which no active therapy is currently available. This so-called sacroplasty was first reported in 2002 as a single case report. Six other cases with this indication have been reported in the Anglo-American literature so far. This article is the first description of this technique in the German literature. It comprises the description of two typical cases highlighting the difficulties in diagnosis, surgical technique, and possible complications. Both patients were treated successfully and had a dramatic pain relief within several hours.

Medium-term results of percutaneous vertebroplasty in multiple myeloma

Vertebral compression fractures (VCFs) are common in multiple myeloma (MM). Percutaneous vertebroplasty (PVP) is used to stabilize vertebral collapse and treat the pain. Few studies have been carried out on PVP in MM and follow-up has tended to be short. We have prospectively evaluated the safety and efficacy of PVP in the VCFs resulting from MM or plasmacytomas. Nineteen PVP were performed in 12 consecutive patients. We monitored their pain and functional status using visual analog (VAS) and Eastern Cooperative Oncology Group (ECOG) scale, respectively. For a subjective assessment, every patient was asked about his/her degree of satisfaction. The mean age of the participants was 66 yr. Significant improvement occurred 1 d after PVP according to the VAS score (7.5 pre-PVP to 3.7, P < 0.0001) and ECOG assessment (3.1 to 2.5, P = 0.002). This significant improvement was maintained after 3.2 yr of follow-up. Sixty-three percent of patients were highly satisfied with the result of the PVP and 37% were satisfied. The peri-operative mortality was 0%. Leakage of the cement outside of the vertebral body was noted in 16 of 19 injected vertebrae (84%) but none of the patients developed any clinical or neurological symptoms. At the last follow-up, no further collapse in the treated or neighboring vertebrae was noted. VCFs caused by MM or plasmacytomas can be effectively treated by vertebroplasty. PVP is associated with early clinical improvement of pain and function and can be maintained after a long follow-up without major procedure-related complications.

[Principles of OSG arthrodesis in cases of joint infection]

A chronic empyema of the ankle joint often develops after an open fracture or surgery. In the case of the destruction of the joint due to an infection, an arthrodesis should be performed. Normally we use an external fixator with two bone-nails placed into the calcaneus and two into the tibia. The arthrodesis is distracted and Septopal is permanently implemented. At 4-6 weeks after surgery the Septopal is removed, with distraction being reduced and a cancellous bone-graft taken from the dorsal iliac crest is performed to fill the bony defect. After bone healing, the external fixator is removed and the patient mobilized in a brace. Initially, weight-bearing is limited to 10 kg but is increased gradually to full weight. The brace is used for 6-9 months; later the patient is mobilized in orthopaedic shoes. In difficult cases, also in combination with a malposition which has to be corrected or a lengthening of the lower limb, we use the Ilizarov fixator. From 1993 to 2003 we performed arthrodeses of the ankle joint due to infectious destruction in 107 cases. In 82.2%, the empyema was caused by a fracture of the ankle joint and the following treatment. In 58% of the patients, we saw associated diseases such as obesity, alcohol abuse, diabetes and malposition of the foot. In 55% we found Staphylococcus aureus. In 86%, we used the external AO-fixator, in 14% the Ilizarov fixator. The patient retained the fixator for an average of 128 days. In our study, 92.1% of the 101 patients who had completed therapy showed a good stability an average of 4.5 years after the arthrodesis. In 5% we found partial stability, while three patients had to be amputated. In 57 patients (56.4), an arthrosis of the tarsal bones was found, and 38 patients (54.3%) of the 70 patients who at the time of the arthrodesis were still working could return to work.

Use of Gentamicin in the Treatment of Access-Port Infections

BACKGROUND

A therapy concept for access-port infections is presented.

METHODS

Between January 2001 and May 2005, 556 adjustable gastric bands were placed laparoscopically, and access-port infection data were analyzed. 6 early infections and 1 late infection occurred. 2 early infections were treated successfully with placement of a PMMA-chain at the port-site--without port removal. 2 other early infections were treated successfully with port removal and later reconnection; however, infection recurred at the access-port soon after reconnection, so a PMMA-chain was positioned around the port. The last 2 early infections were treated successfully by port removal and later connection of a new access-port surrounded by a PMMA-chain. The late access-port infection appeared to be caused by gastric erosion.

RESULTS

Complete healing was achieved in all cases of early infection, and follow-up revealed no complications with subsequent band adjustments. The gastric erosion required removal of the entire banding system.

CONCLUSION

For early port infection, the placement of a PMMA-chain around the subcutaneous port appears to be a safe and effective approach that is less invasive than the usual port removal under general anesthesia. Placing the PMMA-chain is a rapid and simple procedure that allows retention of the original access-port. Once local healing is complete, the port can then be accessed easily and safely for band inflation.

Osteomyelitis der Mittelhand- und Handwurzelregion

AIM

Because of the low prevalence, there is poor evidence on the effective management of bone and joint infections of the carpus and metacarpus. We therefore studied the outcomes of patients undergoing surgical treatment at our department.

METHOD

We conducted a retrospective study on all patients operated on because of osteomyelitis of the carpus and metacarpus between January 1998 and June 2004. Main study endpoint were the infection control rate at end of treatment and at time of follow-up.

RESULTS

Of eleven subjects (nine men, two women) with a median age of 43 years (range, 19 to 79 years) serial débridement with temporary wound closure and surgical fixation proved successful in ten cases. We identified causative pathogens in ten cases (S. aureus: n = 3, P. aeruginosa: n = 3, mixed: n = 4) by intraoperative biopsy. Eight subjects received local or free tissue flaps. A 73 year old man died in hospital. Follow-up information was available for eight patients after a median of 19.5 months (range: 3 to 61 months). Seven of them did not show signs of recurrent infection.

CONCLUSION

Adhering to accepted standards of treating osteomyelitis, satisfactory control rates in carpal and metacarpal infection can be achieved while salvaging the hand.

Therapy with gentamicin-PMMA beads, gentamicin-collagen sponge, and cefazolin for experimental osteomyelitis due to Staphylococcus aureus in rats

INTRODUCTION

In spite of new surgical techniques and recently developed antibiotics, there is no satisfactory solution for the treatment of chronic posttraumatic osteomyelitis. The introduction of local antibiotic treatment with gentamicin-PMMA beads according to Klemm has provided new stimuli for the treatment of chronic osteomyelitis. With the development of collagen as an absorbable carrier substance, the disadvantages of the rigid carrier system became evident. Due to the varying surgical techniques and different forms of adjuvant therapy, it is difficult to assess therapeutic methods and compare different studies. Therefore, it seemed appropriate to study the effect of local treatment with different antibiotic carriers in the setting of an animal study.

MATERIALS AND METHODS

The proven rat model for Staphylococcus aureus-induced osteomyelitis was used to compare the results of monotherapy with cefazolin, gentamicin-PMMA beads, or gentamicin-containing collagen sponge with the combination of local and systemic antibiotic treatment.

RESULTS

Single-agent therapy with parenterally administered cefazolin reduced the CFU from 3.7 x 10(6) to 2.9 x 10(4) g(-1) of tibial bone. The effect on osteomyelitis was more pronounced with the local application of antibiotics. The best results were achieved with the gentamicin-containing collagen sponge which reduced the bacterial colony count to 1.4 x 10(2) CFU/g compared with 9.8 x 10(2) CFU/g achieved with gentamicin-PMMA beads. The effect was most marked using a 4-week combination therapy with local application of the gentamicin-containing collagen sponge and systemic administration of cefazolin. In 9 of 11 animals, no bacteria could be detected in the bone.

CONCLUSION

Each of the treatment modalities resulted in a significant therapeutic effect. Due to its ability to quickly release large amounts of gentamicin, the flexible gentamicin-containing collagen sponge proved to be superior to the rigid PMMA system. Although the gentamicin-containing collagen sponge provided high antibiotic concentration at the site of implantation, an additive effect was attained when combined with systemic antibiotic treatment.

Results of vancomycin-impregnated cancellous bone grafting for infected tibial nonunion

INTRODUCTION

Bone grafting plays a critical role in promoting bone healing in infected nonunion, although recurrent infection is of concern. Cancellous bone grafting as an antibiotic delivery system has been reported as an effective method to combat infections. In this study, we report the clinical results of vancomycin-impregnated cancellous bone grafting for the treatment of infected tibial nonunion.

MATERIALS AND METHODS

Between January 1996 and March 2001, 18 patients with infected tibial nonunion treated with vancomycin-impregnated cancellous bone grafting were available for follow-up. According to the Cierny-Mader classification, all patients belonged to type IVA and IVB osteomyelitis. Adequate debridement, stabilization with external fixation, and staged vancomycin-impregnated cancellous bone grafting were used in all patients. Regular clinical and radiographic follow-ups were conducted.

RESULTS

Infection control was obtained in all 18 patients with a 100% infection arrest rate. Bone union was achieved in 13 of 18 patients at an average of 5.8 months. Bone union was obtained subsequently in the remaining five patients after closed nailing in four, and plating and bone grafting in one patient. Radiographs showed good consolidation and hypertrophy of grafted bone at an average follow-up of 48 months.

CONCLUSION

We conclude that vancomycin-impregnated cancellous bone grafting is a safe method for the treatment of infected tibial nonunion.

[Treatment of urinary stress incontinence in women with a periurethral implant]

OBJECTIVE

The aim of this article is the comprehensive information about different bulking substances and their use for the treatment of genuine stress urinary incontinence in women.

DESIGN

The review summarizes various materials used for this purpose, methods of their application, possible complications and results of clinical studies of implants.

SETTING

Department of Obstetrics and Gynaecology of Charles University and Faculty Hospital Bulovka takes part in the development of the new metacrylate of Czech origin.

SUBJECT AND METHOD

Current scientific literature as listed in the article.

CONCLUSION

Implants seem to be a useful alternative method in the treatment of the genuine stress incontinence in women.

Percutaneous vertebroplasty: a novel treatment for acute vertebral fractures

Acute vertebral fracture is a painful and debilitating complication of osteoporosis which has been extremely difficult to manage. Percutaneous vertebroplasty--injecting cement to stabilise the fractured end plate--represents a major management breakthrough. We report the first four patients with osteoporotic vertebral fractures treated by this technique at our hospital. They are, to our knowledge, among the first to be successfully treated in this way in Australia.

Physical properties of solid dispersion of a nonsteroidal anti-inflammatory drug (M-5011) with Eudragit E

Some acidic nonsteroidal anti-inflammatory drugs (NSAIDs) are poorly soluble in the stomach. In this study, M-5011, d-2-[4-(3-methyl-2-thienyl) phenyl] propionic acid, was used as a model substance. To increase the dissolution rate of M-5011, a solid dispersion of M-5011 was prepared by the powder mixing method using Eudragit E-100 (aminoacryl methacrylate copolymer) as a carrier. Evaluation by X-ray diffraction and differential scanning calorimetry (DSC) revealed that M-5011 easily formed a solid dispersion with E-100. The dissolution behavior of a physical mixture prepared immediately after mixing and the mixture stored for 14 days at 40 degrees C were examined. It was observed that the former, containing a great deal of E-100, showed a fairly good dissolution behavior, and the latter had a better dissolution rate. The mechanism of the interaction of M-5011 and E-100 was investigated by infrared (IR) spectroscopy and nuclear magnetic resonance (NMR). The interaction was simulated by NMR using a monomer of Eudragit E-100.

[Therapy of bacterial knee joint infection by radical synovectomy and implantation of a cemented stabilized knee joint endoprosthesis]

INTRODUCTION

The report presents an alternative to the treatment of joint destruction in cases of knee joint empyema by resection or arthrodesis: implantation of a stabilised knee prosthesis using antibiotic-loaded bone cement for fixation.

METHOD

From 1985 to 1997 a total of 33 knees in 32 patients (21 female, 12 male) were treated for knee empyema by radical synovectomy and implantation of a stabilised knee prosthesis fixed in position with antibiotic-loaded bone cement. The antibiotics were chosen according to the antibiogram of the pathogen. In all these cases the infections had not responded to previous treatment. The criterion for success was the elimination of infection. The follow-up period ranged from 2 to 15 years.

RESULTS

Of 33 infected knees 31 (93.9%) were followed up. In 22 cases (71.0%) the infection was eliminated by primary surgery. In five cases (16.1%) further exchange operations were necessary to eliminate the infection. In four cases (12.9%) preservation of the joint was not possible.

CONCLUSION

Uncontrolled infection in cases of knee empyema and destruction of the joint can be treated by radical synovectomy and implantation of a stabilised knee prosthesis using antibiotic-loaded bone cement for fixation. The success rate corresponds to the results of one-stage exchange arthroplasty to treat periprosthetic infection of knee prostheses. This therapy should be performed only in specialised centres which have the facilities and personnel essential for accurate bacteriological diagnosis and recommendation.

Transarterial embolization with HEMA-MMA of variant convexity-superior sagittal sinus dural arteriovenous fistula--case report

A 62-year-old male presented with a variant dural arteriovenous fistula (DAVF) within the wall of the convexity-superior sagittal sinus, fed by branches of the bilateral external carotid arteries and only cortical venous drainage despite the presence of a patent sinus. Transarterial embolization with poly(2-hydroxyethyl methacrylate-co-methyl methacrylate) (HEMA-MMA) was performed, resulting in complete obliteration of the DAVF. Embolization with HEMA-MMA is an effective and safe procedure for the treatment of DAVF.

[Results of one-stage endoprosthesis revision in periprosthetic infection cause by methicillin-resistant Staphylococcus aureus]

OBJECTIVE

Are the results of one-stage exchange arthroplasties to treat periprosthetic infection caused by methicillin-resistant Staphylococcus aureus (MRSA) comparable to bacteriologically unselected studies of one-stage exchange operations?

METHOD

From 1996 to 1997 twenty patients with a periprosthetic infection caused by methicillin-resistant Staphylococcus aureus (MRSA) were treated at the ENDO-Klinik by an one-stage exchange arthroplasty. Mean follow-up of fifteen one-stage exchange total hip replacements and 5 one-stage exchange total knee replacements was 16 months. The patients were examined by means of clinical, laboratory-chemical and radiological tests. In addition, postoperative joint aspiration was performed on 14 patients.

RESULTS

In 11 cases (61%) the periprosthetic infection was treated successfully with only one one-stage exchange operation. In cases with persisting infection the period between the first exchange arthroplasty and the repeated clinical manifestation of the infection (second exchange operation) was 2 months on average. 93% of the joint aspirations (n = 14), performed on average 4 weeks postoperatively, correlated with the result of the follow-up tests.

CONCLUSION

Periprosthetic infection with MRSA is a problematic infection. Because of the reduced therapeutic possibilities it is associated with a higher rate of recurrence than the unselected group of patients as a whole [6, 11, 16, 17, 19, 20]. The authors recommend one-stage exchange arthroplasty using a combination of vancomycin and ofloxacin as admixture to polymethylmethacrylat (Refobacin Palacos R). This procedure does, however, need further development. Intraoperative use of an antiseptic and systemic administration of rifampicin, as recommended by Zimmerli [23] is a further possibility.

[Bacterial coxitis caused by Salmonella enteritidis. Case report and differential diagnostic considerations]

Secondary haematogenous joint involvement is seen in less than 1% of patients with Salmonella infections. These atypical infections are frequently encouraged by pre-existing local or systemic disease. We present a case of a patient with known alcohol abuse who developed a septic infection of her right hip requiring resection of the femoral head. Histologic analysis showed signs of pre-existing osteonecrosis probably induced by alcohol intake. Cartilage and bone were invaded and destructed by an aggressive granulation tissue. Initially, a biopsy evaluated without knowledge of the positive bacteriological result had been interpreted as indicative of a tumour. The onset, clinical course, diagnosis and therapy of joint involvement by Salmonella are discussed with regard to our case and the relevant literature. This case illustrates the necessity for clinicians to share all their information about the patient with the pathologist.

[Development of gentamicin-resistant Small Colony Variants of S. aureus after implantation of gentamicin chains in osteomyelitis as a possible cause of recurrence]

AIM

Recently, S. aureus small colony variants (SCVs) were reported to persist within cultured endothelial cells and to cause persistent and antibiotic resistant infections in humans. Because gentamicin can very reproducably select for electron transport deficient SCVs as shown in earlier in vitro experiments, we searched for SCVs in a patient with chronic osteomyelitis, who received gentamicin beads.

METHOD

Special culture and identification procedures for determination of SCVs were used, including testing of the S. aureus specific nuc gene, pulsed field gel electrophoresis (PFGE) as a typing method and characterization of the auxotrophism of the SCVs.

RESULTS

In a case of a 34-year-old patient with chronic osteomyelitis who had previously been treated with gentamicin beads, menadione auxotrophic S. aureus SCVs as well as wild type S. aureus were recovered in multiple bone specimen. All different colony types isolated from simultaneous or from sequential specimen were shown to be clonal by PFGE.

CONCLUSION

Recovery of S. aureus SCVs from a patient treated with gentamicin beads suggests that the slow release of gentamicin into the local environment may be an efficient way to select for and/or induce SCVs. These data should alert physicians to also consider SCVs when a treatment failure occurs in a patient that has received gentamicin beads.

Prospective study of two retrograde endodontic apical preparations with and without the use of CO2 laser

This article covers a 4-year study that reports 320 cases in which endodontic surgery was performed for residual apical lesions or lesions that could not be treated in a conventional way. Four groups of 80 teeth each were formed and they were followed up after a 12-month interval. The first group comprised cases treated with a micro bur, retrograde filling and IRM; the second, cases treated at the apical and radicular portions with a CO2 laser; the third, cases in which the retrograde cavity was prepared with an ultrasonic device instead of a micro bur; and the fourth group comprised cases treated in a similar way to the second group, i.e., cases treated at the apical and radicular portions, but with a CO2 laser instead of a micro bur. After 12 months, the results showed a better prognosis with ultrasonic treatment. Regardless of technique, the CO2 laser did not improve the healing process.

Percutaneous vertebroplasty: state of the art

Vertebroplasty is an effective new radiologic procedure consisting of the percutaneous injection of a biomaterial, usually methyl methacrylate, into a lesion of a vertebral body. This technique allows marked or complete pain relief and bone strengthening in most cases. The principal indications for vertebroplasty are osteolytic metastasis and myeloma, painful or aggressive hemangioma, and osteoporotic vertebral collapse with debilitating pain that persists despite correct medical treatment. Radiography and computed tomography must be performed in the days preceding vertebroplasty to assess the extent of vertebral collapse, the location and extent of the lytic process, the visibility and degree of involvement of the pedicles, the presence of cortical destruction or fracture, and the presence of epidural or foraminal stenosis caused by tumor extension or bone fragment retropulsion. Leakage of methyl methacrylate during vertebroplasty may cause compression of adjacent structures and necessitate emergency decompressive surgery; thus, the procedure should be performed only in a surgical center. The decision to perform vertebroplasty should be made by a multidisciplinary team because the choice between vertebroplasty, surgery, radiation therapy, medical treatment, or a combination thereof depends on a number of factors. Radiologists need to be aware of the various indications for vertebroplasty and of potential future developments and applications of the procedure.

Chronic inhalation toxicity and oncogenicity of methyl methacrylate in rats and hamsters

Male and female Fischer 344 rats were exposed to methyl methacrylate (MMA) monomer vapours at 0, 25, 100 and 400 ppm, 6 hr/day, 5 days/wk for 24 months and male and female Golden hamsters were exposed to similar vapour concentrations of MMA for 18 months. Parameters monitored throughout the study included clinical signs, individual body weights, haematology, clinical chemistry (rats only) and urinalyses (rats only). 10 rats per sex per exposure group were killed after 13 and 52 wk of exposure and all surviving rats were killed during wk 104-106. All surviving hamsters were killed at wk 78. Mortality and haematological, clinical chemistry and urinalyses parameters were not affected by MMA exposure. Body weights of male rats were not affected by exposure to MMA while body weights of female rats exposed to 400 ppm were lower than control values after wk 52. Male and female hamsters exposed to 400 ppm had body weight decreases ranging from 9 to 12% after wk 48. The nasal cavity was identified as the target organ for chronic toxicity in male and female rats exposed to 100 or 400 ppm. The microscopic nasal cavity changes occurred primarily in olfactory epithelium lining the dorsal meatus and consisted of degeneration of neuroepithelium, basal cell hyperplasia and atrophy of Bowman's glands. Hamsters did not have demonstrable nasal cavity microscopic changes. Chronic exposure to MMA vapour did not cause tumours in either rats or hamsters.

Release of daunorubicin from polymethylmethacrylate for the improvement of the local growth control of bone metastasis animal experiments

Bone metastases are a sign of advanced tumor disease. Surgical therapy is only occasionally curative. Therefore, the therapeutic goals are a limited surgical excision, immediate mobilization, effective stabilization and the avoidance of local recurrence. We investigated the effect of the anthracycline daunorubicin (DNR) in conjunction with polymethylmethacrylate (PMMA) in vitro and in animal experiments for regional control of bone metastases. Previous experiments of local chemotherapy in bone metastases using methotrexate (MTX) were done by Langendorff and Hernigou. In our own experiments we improved the release of daunorubicin from polymethylmethacrylate in vitro and in vivo up to 90% by adding mannitol. In in vivo experiments we investigated the combination of DNR and PMMA in athymic nude mice and Wistar rats. Cells from human breast cancer, bronchial carcinoma, nephroma, and soft tissue sarcoma were subcutaneously implanted bilaterally under the dorsal skin of nude mice. After reaching a diameter of 0.5 cm, the tumors were marginally excised, leaving microscopic tumor residuum behind. The tumor cavities were either filled with PMMA or alternatively with DNR-PMMA. The goal was to avoid tumor recurrence in the DNR-PMMA filled resection cavities. The number of recurrences was significantly lower in the DNR-PMMA treated animals, except in the breast cancer group. Additionally we implanted a rat sarcoma intrafemorally into Wistar rats. After 17 days the tumor was marginally excised and the resection cavity was filled with either DNR-PMMA or PMMA alone. The therapeutic goal was to prevent local recurrence. Histological and pharmacological tests concerning toxicity and drug distribution within the body completed the study. We concluded that the addition of daunorubicin to PMMA supplements surgical resection. We were able to reduce the number of, or delay recurrences in our animal models. Systemic side effects could be minimized despite the achievement of high local drug concentrations.

Percutaneous vertebroplasty for osteolytic metastases and myeloma: effects of the percentage of lesion filling and the leakage of methyl methacrylate at clinical follow-up

PURPOSE

To determine whether the percentage of vertebral lesion filling and the leakage of methyl methacrylate have any clinical significance at follow-up.

MATERIALS AND METHODS

Forty percutaneous vertebroplasties were performed for metastases (30 cases) and myeloma (10 cases) in 37 patients. A computed tomographic scan was obtained 1-8 hours after methyl methacrylate injection and was used to assess the percentage of lesion filling by methyl methacrylate and the leakage of methyl methacrylate into the epidural tissues, neural foramina, intervertebral disks, venous plexus, and paravertebral tissue. The results were correlated with those obtained at clinical follow-up.

RESULTS

Partial or complete pain relief was sustained in 36 of 37 patients. Pain relief was not proportional to the percentage of lesion filling. Clinical improvement was maintained in most patients. The 15 epidural leaks, eight intradiskal leaks, and two venous leaks of methyl methacrylate had no clinical importance. Two of eight foraminal leaks produced nerve root compression that required decompressive surgery. One of 21 paravertebral leaks produced transitory femoral neuropathy.

CONCLUSION

Pain relief can occur despite insufficient lesion filling. In most patients, intradiskal and paravertebral leaks of cement had no clinical importance.

Asymptomatic cervical haemangioma treated by percutaneous vertebroplasty

We report a 17-year-old asymptomatic patient with a partially collapsed seventh cervical vertebra due to a haemangioma revealed by conventional radiographs performed for army enrollment. Given radiological evidence of aggressiveness, percutaneous vertebroplasty by injection of methyl methacrylate cement was performed to prevent complications. CT a year later showed no progression of the lesion. The patient remains asymptomatic.

Acrylic vertebroplasty in symptomatic cervical vertebral haemangiomas: report of 2 cases

We report two cases of acrylic vertebroplasty in symptomatic cervical vertebral haemangiomas. In both cases significant improvement of symptoms was rapid. One patient was able to return to work.

Spinal metastases: indications for and results of percutaneous injection of acrylic surgical cement

PURPOSE

To determine the efficacy of percutaneous vertebroplasty in treating spinal metastases that result in pain or instability.

MATERIALS AND METHODS

Thirty-seven patients (20 men, 17 women; aged 33-86 years) underwent 52 percutaneous injections of surgical cement into a vertebra (vertebroplasty) with fluoroscopic guidance in 40 procedures. Vertebroplasty was performed for analgesia in 29 procedures, stabilization of the vertebral column in five procedures, and both in six procedures.

RESULTS

Twenty-four of the 33 procedures performed for analgesia that were evaluated resulted in clear improvement; seven, moderate improvement; and two, no improvement. Improvement was stable in 73% of patients at 6 months. In the procedure performed for stabilization, no displacement of treated vertebrae was observed (mean follow-up, 13 months). Three patients had transient radiculopathy due to cement extrusion, and two patients had transient difficulty in swallowing.

CONCLUSION

Vertebroplasty of metastases is a minimally invasive procedure that provides immediate and long-term pain relief and contributes to spinal stabilization.

Preoperative percutaneous injection of methyl methacrylate and N-butyl cyanoacrylate in vertebral hemangiomas

PURPOSE

To investigate the usefulness of preoperative percutaneous injections in vertebral hemangiomas.

METHODS

Four patients presented with complicated vertebral hemangioma (spinal cord compression in three cases, intermittent spinal claudiction in one case). A three-part treatment was performed: initially, arterial embolization in three cases; 1 day later, percutaneous injections of methyl methacrylate into the vertebral body to strengthen it and of N-butyl cyanoacrylate into the posterior arch to optimize hemostasis during surgery; finally, the day after percutaneous injections, decompressive laminectomy and epidural hemangioma excision (when present).

RESULTS

Laminectomy was performed with minimal blood loss. The epidural component present in three cases was excised without any difficulty. The follow-up (average, 20 months) showed no evidence of vertebral collapse.

CONCLUSION

Percutaneous injections of methyl methacrylate and N-butyl cyanoacrylate might be useful before surgery for vertebral hemangiomas.

[Treatment of wrinkles by Artecoll implant and resurfacing with the CO2 laser]

In general, all biological materials are resorbed in places where they do not belong. Therefore, artificial substances have to be implanted under deep skin folds and skin defects in order to achieve a permanent skin augmentation. Artecoll, a suspension of polymethylmetcrylate (PMMA)-microspheres in collagen solution, has been proven, for more than 5 years, to underlay wrinkles effectively without noticeable side-effects. Small wrinkles around the eyes, the mouth and cheeks, however, have to be treated by dermabrasion, chemical peel or vaporization by CO2-laser. Using all three methods, the effectiveness depends on the depth of skin traumatisation. Resurfacing using the CO2-laser has the advantage of absolute precision, no bleeding, less swelling and faster healing-but still high costs.

[27 years experiences with transtympanic aminoglycoside treatment of Menière's disease]

BACKGROUND

Severe unilateral Menière's disease is successfully treated intratympanically with ototoxic antibiotics. Gentamicin sulfate (Refobacin) gives the best results. The only disadvantage is that gentamicin may damage hearing in the treated side. Therapy is easier in patients with marked hearing loss prior to treatment.

PATIENTS AND METHOD

Since 1976 we treated 61 patients by injecting 8-12 mg Refobacin (0.2-0.3 ml) into the external auditory meatus between two and five times per day. By creating slight pressure (Politzer bag) the liquid is transported into the middle ear via a ventilating tube. From here it penetrates through the windows. The slightest indication of inner ear reaction was grounds for immediately terminating treatment.

RESULTS

In 54 of our 61 patients (follow-up 2-17 years) we were completely successful. Three further patients continued having very rare and weak spells, yet we regard them as being practically healed. We did not succeed in four of our cases. Twenty-nine patients suffered hearing loss. Hearing was mostly poor prior to therapy.

CONCLUSIONS

Transtympanic gentamicin therapy provides very good results in severe cases of unilateral Menière's disease. Spells of vertigo and vomiting are controlled. We propose individual dosage depending on hearing threshold and intensity of symptoms.

[Percutaneous vertebroplasty]

Vertebroplasty is a new therapeutic method which by way of filling with acrylic cement in the vertebral body gives a stabilization of the vertebra and an antalgic effect in painful lesions involving the spine. Main indications consist of spine angiomas, metastases and osteoporotic fractures involving the vertebral body. In most patients, vertebroplasty gives a very good and durable antalgic effect as in cases of angiomas or metastases as in post-therapeutic sequellae in malignant hematosarcomas. In osteoporotic fractures, antalgic effect is obtained very rapidly, but the follow-up is actually insufficient to evaluate the long term benefit.

PMMA microspheres (Artecoll) for skin and soft-tissue augmentation. Part II: Clinical investigations

Artecoll is an injectable implant for long-lasting correction of wrinkles and other skin defects. Artecoll consists of fine polymethyl-methacrylate (PMMA) microspheres suspended 1:3 in a 3.5% collagen solution. The microspheres are characterized by exceptional surface smoothness, homogenicity, and purity. The size of the microspheres of 30-40 microns diameter is small enough to allow subdermal implantation using a 27-gauge needle. Phagocytosis and dislocation of the implant is prevented by fast encapsulation of each single microsphere with connective tissue. Increased scarring but no granuloma formation has been detected as is common with other injectable implants with irregular surfaces. The experience from more than 600 patients and a prospective study in 118 patients with 200 implantation sites were evaluated. The good early results have continued for 5 years. Of the patients evaluated, 89.5 percent were satisfied and would ask for the treatment again. The overall complication rate is very low, and prolonged redness or visible granules are due to implantations that are too superficial. Other applications in soft-tissue augmentation are discussed.

[Treatment of periprosthetic infection of the hip using one-stage exchange surgery]

This article presents the theoretical microbiological principles involved in the pathogenesis of periprosthetic infection, the role of microbiology in diagnosing this disease, and factors requiring special consideration when selecting topical antibiotics. It also describes the operative technique of one-stage exchange arthroplasty using antibiotic-loaded acrylic cement and the results achieved with this method to date.

Ridge preservation using HTR synthetic bone following tooth extraction

Use of HTR (synthetic bone graft material) has been described to make tooth extraction a more controlled, regimented procedure. Strict adherence to surgical technique, with emphasis on appropriate suturing, is necessary to produce consistently successful results. A variation of an interrupted suture technique, the double-mattress stitch, is described in detail to achieve these results. This suturing method is replicable and applicable to most areas of the mouth. This technique is more challenging (but not impossible) to perform in areas that are difficult to access, such as in maxillary third molar regions. This stitch is essential for closing the extraction site and containing the graft material during initial healing. An ideal bone graft material should prevent postextraction osteitis, and maintain bone in the extraction area and proximal to this site. HTR satisfied these requirements.

[Results of long-term therapy of chronic, post-traumatic osteomyelitis with gentamycin PMMA chains]

From 1977 to 1983, 173 patients suffering from chronic posttraumatic osteomyelitis were treated by local debridement and implantation of septopal beads; 102 patients were subsequently evaluated after follow-up periods of between 4 and 10 years. In 89.2% of these cases cure was achieved during the initial hospital stay. In 15.7% further debridements were necessary during the initial hospital stay to manage infection. In 91 patients there was no early recurrence until 1983. After 1983 only 7 patients had late recurrences. At the time of follow up 95 patients (94.5%) did not show any signs of infection. It was necessary for 9 patients to change their profession because of the disease. Full use of the extremity involved was reported by 45 patients, and some slight limitations by 46. In 11 cases the patients could not use the extremity involved in activities of daily living. In mono-infections (87.2%) and in infection with multiple different pathogen chains (82%) Staphylococcus aureus was by far the most common pathogen. Our findings indicate that both the outcome and the prognosis score are significantly better after the treatment regimen used than after other treatment modalities.

Efficacy of slow-releasing anticancer drug delivery systems on transplantable osteosarcomas in rats

New drug delivery systems for cis-diamminedichloroplatinum (CDDP) incorporated into vehicles, such as polymethylmethacrylate (PMMA), fibrin glue (F.G.), alpha-tricalciumphosphate (TCP) and ethylenevinyleacetate copolymer (Polymer) were examined using a rat osteosarcoma model. The materials containing CDDP were directly implanted into the tumors or subcutaneous tissue of rats, and the inhibitory effects on tumor growth and lung metastasis were evaluated. Data on in vitro kinetics of CDDP release revealed good results for both TCP and F.G., and the release pattern from TCP to be most appropriate for a slow-releasing drug delivery system. This was supported by the results of the implantation experiments, whereby the direct implantation of TCP containing CDDP (CDDP-TCP) into tumors, gave significantly better inhibitions of tumor growth and metastasis than either non-treatment (P < 0.01) or subcutaneous implantation (P < 0.05). In a second experiment, using different administration procedures, different inhibitory effects on tumor growth and lung metastatic potency were observed with intra-arterial and intravenous CDDP administration, as well as with CDDP-TCP implanted subcutaneously. Suppression effects of CDDP (10 mg/kg)-TCP directly implanted into tumors were equal to those of intra-arterial (2.5 mg/kg) and intravenous (5.0 mg/kg) administrations. The present results suggest CDDP-TCP implantation to be effective as a slow-release drug delivery system for inhibiting tumor growth and metastasis, and that it should be a useful adjuvant to conventional i.v. or i.a. chemotherapy.

[The value of intramedullary boring and intramedullary splinting in revision of infected pseudarthroses]

In the treatment of pseudarthrosis with only a segmental loss of bone elements a reconstruction by the Ilizarov method is too complicated, and simple decortication and plastic surgery with cancellous bone grafting is usually too slow. With reference to three cases, it is shown that simultaneous debridement and bone reaming can improve clearance of the infection. Using decortication and autologous cancellous bone grafting, it is possible to leave the center of the bone free by temporarily inserting a silicon tube. As a result cancellous bone can be saved and the danger of a relapse will be minor. In two cases this technique with the central silicon tube was applied for the first time within the scope of plastic surgery with cancellous bone. If, as in the third case, there is enough bone substance in the region of the pseudarthrosis with swelling of the soft tissue or fistulation, in selected cases reaming of the bone cavity and decortication are all that is necessary. The average length of follow up was 19 months. Only in one of our cases did local inflammation recur 9 months after clearance, which healed rapidly with conservative procedures. The other patients had no episodes of this nature. In our group, the patients achieved full weight-bearing on their leg without external support in an average of 5 months. Compared with another study conducted in Liestal, in which a similar group (infected pseudarthrosis with bone defects of 4-11 cm) was treated by the Ilizarov technique, shortening of the treatment by an average of 4 months was obtained.(ABSTRACT TRUNCATED AT 250 WORDS)

Innovations in acrylic bone cement and application equipment

A new bone cement was developed with the purpose of reducing the adverse biological effects during cementation of implants. This bone cement is characterized by lower exotherm, low release of monomer, low residual content of monomer, and retained physical properties. The essential innovation was substitution of half of the methylmethacrylate (MMA) in the monomer with long chain, high molecular weight, less volatile, and less soluble methacrylates (n-decylmethacrylate, isobornyl-methacrylate), as well as alteration of the accelerator system to a mix of dihydroxypropyl-p-toluidine and N,N-dimethyl-p-toluidine. The powder contains butylmethacrylate-MMA copolymers. These measures lower the glass-transition temperature, and permit more complete mixing in an integrated package, mixing, and delivery system consisting of a vacuum packed, double chamber pouch. The porosity was reduced to about 2% and the largest voids measured 0.1 mm. The polymerization exotherm was reduced to 58 degrees C. The compressive strength was 82 MPa, the four-point bending strength 55 MPa, the flexural modulus 2.24 GPa, the tensile strength 32 MPa, and the shear strength 36 MPa. The fracture toughness was 0.89 MPa square root of cm. These mechanical properties together with the fatigue life were on level with manually mixed, conventional PMMA bone cements.

Recurrence of giant-cell tumors of the long bones after curettage and packing with cement

The nine-year experience with sixty patients who had had a giant-cell tumor of a long bone was reviewed to determine the rate of recurrence after treatment with curettage and packing with polymethylmethacrylate cement. The demographic characteristics, including the age and sex of the patient and the site of the tumor, were similar to those that have been reported for other large series. An average of four years (range, two to ten years) after the operation, the over-all rate of initial local recurrence was 25 per cent (fifteen of sixty patients). Patients who had had a tumor of the distal aspect of the radius had a higher rate of recurrence (five of ten) than those who had had a tumor of the proximal aspect of the tibia (seven [28 per cent] of twenty-five) or of the distal part of the femur (three [13 per cent] of twenty-three). Higher rates of recurrence were also noted for patients who had had a pathological fracture (three of six), those who had had a Stage-III tumor according to the classification of Campanacci et al. (six of sixteen), and those who had not had adjuvant treatment with either a high-speed burr or phenol (eight of nineteen). Patients who had had an initial recurrence after packing with cement had a low rate of secondary recurrence when the initial recurrence had been treated with a wide resection or a second intralesional procedure (zero of ten and one of five patients, respectively), after an average of three years (range, ten months to eight years). No patient had a multicentric tumor or metastasis.(ABSTRACT TRUNCATED AT 250 WORDS)

Percutaneous vertebroplasty with acrylic cement in the treatment of a Langerhans cell vertebral histiocytosis

A 25-year-old man developed multiple eosinophilic granuloma of bone including vertebral and sacral localization. Radiotherapy was initially administered. One year later, a relapse occurred in another vertebrae which was previously irradiated. Percutaneous vertebroplasty was, for the first time to our knowledge performed, in this indication, with a good clinical result with follow-up now for one year. We emphasize that such treatment is permissible only in symptomatic, progressive lesions, with threatened decompensation of spinal stability. This technique should be used only on an adult.

Comparison of the inflammatory response to particulate polymethylmethacrylate debris with and without barium sulfate

Particulate polymethylmethacrylate debris has been implicated in the inflammatory response observed surrounding loosened cemented implants. The rat subcutaneous pouch model and the Howie implant model (used to study bone resorption) were used to quantify the response to mechanically produced endotoxin-free polymethylmethacrylate debris with and without 10% (wt/vol) BaSO4. In the rat subcutaneous pouch model, the inflammatory response to polymethylmethacrylate particles containing BaSO4 was greater than the response to plain polymethylmethacrylate particles of similar size. Increased inflammation was measured by leukocyte counts and levels of prostaglandin E2, tumor necrosis factor, and neutral metalloprotease. In addition, particulate polymethylmethacrylate with BaSO4 caused significantly greater bone resorption in the Howie model than did particulate plain polymethylmethacrylate. In in vitro studies, particulate polymethylmethacrylate with BaSO4 stimulated more prostaglandin E2, neutral metalloprotease, and tumor necrosis factor from human monocytes in culture and stimulated greater proliferation of synovial cells than did particulate plain polymethylmethacrylate. The presence of BaSO4 appears to significantly intensify the inflammatory response to polymethylmethacrylate debris.

Elution characteristics of gentamicin-PMMA beads after implantation in humans

Seventeen patients had gentamicin-PMMA beads implanted for treatment of orthopedic infections. The authors found that beads implanted in patients for 3 to 36 weeks were capable of eluting high levels of antibiotic after retrieval. Beads that were implanted in patients for less than 10 weeks eluted significantly higher antibiotic levels than beads were implanted for more than 14 weeks. This study supports the local use of these beads in the treatment of musculoskeletal infections.

A composite plug for occluding the femoral canal prior to cementing a total hip femoral component

An improved technique is presented for placement of a combined polyethylene and polymethylmethacrylate (PMMA) plug in the femoral medullary canal prior to cementing the femoral component during total hip arthroplasty. PMMA plugs provide excellent occlusion of the canal, but when used alone they often become excessively long. This can make revision surgery, if it becomes necessary, more difficult. By first inserting a polyethylene plug distally in the femoral canal, followed by a bolus of PMMA, the surgeon can limit the length of the cement portion of the plug in the femoral canal while retaining the advantages of a PMMA plug.

[Value of vertebroplasty combined with surgical decompression in the treatment of aggressive spinal angioma. Apropos of 3 cases]

Vertebral hemangiomas can cause difficult-to-treat neurological complications. We report our experience with three such cases. Patients no. 1 and 2 were females aged 64 and 71 years, respectively; patient no. 1 had a two-year history of weakness in the lower limbs and patient no. 2 had a five-month history of back pain. Both these patients had a pyramidal syndrome in the lower limbs. Patient no. 3 was a 61 year old male with a one-year history of left sciatica. Roentgenograms were suggestive of a hemangioma occupying the entire T8 (cases 1 and 2) or L5 (case 3) vertebra. Computed tomography and magnetic resonance imaging confirmed this diagnosis and showed that patients 1 and 2 had an anterior epidural hemangioma opposite T8 impinging on the spinal cord. In patients 1 and 2, treatment consisted in embolization of T8 followed by transpedicular injection of 6 cc of methylmethacrylate into the body of T8. One cubic centimeter of histoacryl was also injected in each lamina. The third patient had a similar vertebroplasty procedure without prior embolization since he had no epidural hemangioma. One patient (no. 1) developed intercostal neuralgia of several hours duration after the procedure. All three patients subsequently underwent laminectomy (T7-T8 with removal of the epidural hemangioma in cases 1 and 2, L5 in case 3). The pyramidal syndrome resolved within 15 days in patients 1 and 2; the nerve root pain resolved within 48 hours in patient 3.(ABSTRACT TRUNCATED AT 250 WORDS)