Occipital calvarial bone graft in posterior occipitocervical fusion

STUDY DESIGN: Dorsal occipitocervical fusion is associated with a high rate of fusion failure and requires an additional surgical site for donor bone graft harvesting. In this series, an autologous occipital calvarial bone graft obtained from the same occipitocervical incision with contoured metal loops was used in 25 adults to achieve craniovertebral stabilization and fusion. OBJECTIVES: To study the use of autologous occipital calvarial bone grafts in occipitocervical fusion. SUMMARY OF BACKGROUND DATA: Cranial bone grafts have been used successfully in craniofacial reconstruction with good long-term results. In the plastic surgery literature, there are claims that membranous bone grafts are superior to endochondral bone grafts in fusions because of decreased resorption. In recent studies, results have shown successful use of calvarial bone in fusing the upper cervical spine in children. The use of autologous occipital bone in posterior occipitocervical fusions avoids many of the problems associated with traditional donor sites and provides a sufficient quantity of good quality bone for the fusion. This is especially true in the fragile rheumatoid arthritis patient with cranial cervical instability. METHOD: Split-thickness, autologous calvarial bone grafts with contoured loop and cable instrumentation were used for posterior occipitocervical stabilization and fusion in 25 patients, most of whom had rheumatoid arthritis. The calvarial bone graft was harvested from the occipital skull, using a microair impactor, and was secured next to the loop construct. After surgery, all patients were immobilized with external orthoses. RESULTS: None of the patients had hardware failure or complications from the occipital graft procurement. In 22 patients, good alignment, stability, and bony fusion were shown on radiographs. CONCLUSIONS: Occipital calvarial bone graft appears to work as well as other autologous corticocancellous bone grafts routinely used in posterior occipitocervical fusions.     

Bone grafts and bone induction substitutes

The use of bone grafts is the basis of all craniofacial surgery. Bone grafts are used to stabilize the open segments, expand the patient's structural boundaries, and fill defects created by trauma or congenital malformations. Bone grafts are harvested from local or distant sites as indicated. Biomaterial implants are used as bone substitutes when it is not possible to use bone grafts.     

Ethylene oxide-protein adduct formation in humans: influence of glutathione-S-transferase polymorphisms

Autogenous cancellous bone fragments can be compressed rapidly during surgery to create reproducible load-bearing grafts. Of the 32 grafts tested, 10 were constructed of composite cortical-cancellous bovine bone and 22 of cancellous human bone. Compressed composite bovine grafts and compressed human cancellous grafts supported average axial compressive loads of 2148 N and 960 N, respectively. Compared to iliac crest grafts, compression grafts may have better load-bearing capabilities and greater reproducibility. Potential applications include trauma, delayed unions, arthrodesis, and spinal fusions.     

The Ranawat Award. Histology of nine structural bone grafts used in total knee arthroplasty

The cross section radiographs and histology of nine bone grafts were examined to determine whether grafts are durable enough to support a total knee implant when the load is shared by host bone, graft bone, and a stemmed component. All cases had cemented total knee arthroplasties with stemmed components adjacent to bulk grafts. The cases included autografts and allografts, which had been in situ for an average of 41 months (range, 20-62 months). Seven of the grafts were retrieved postmortem from three patients (four knees), and two were retrieved at revision surgery from one patient. The allografts all were intact, but had not revascularized. The autografts were viable bone. New bone was being laid down on the dead graft bone at the periphery of the allografts. No change in the bone to cement interface, no graft collapse, no development of radiolucent lines, and no component loosening occurred in these cases. The promising clinical results of bone grafts in total knee arthroplasties were confirmed by the examination of these grafts at the cellular level. Using stemmed components in bone grafted knee reconstructions may have increased graft durability and protected the grafts from fatigue failure.     

Bovine bone grafting in occipito-cervical fusion for atlanto-axial instability in rheumatoid arthritis

Bovine bone chips (Surgibone) were used in occipito-cervical fusion in nine patients with atlanto-axial instability due to rheumatoid arthritis. The patients were examined with CT 12-15 months after surgery. Graft resorbtion was observed in one patient. The other 8 patients showed preserved grafts, in most cases the grafts appeared to be in contact with the underlying bone. One patient was revised, and at the grafted site a bony bridge was found. In conclusion, the use of bovine chips in posterior occipito-cervical fusion will not lead to predictable bone union. However, there seem to be exceptions to that rule.     

Bone replacement grafts. The bone substitutes

Bone substitutes will play a pivotal role in the future of periodontal regeneration. They are synthetically derived or processed from exoskeletons of other species (xenograft) and are an alternative to autogenous or allogeneic bone replacement grafts. Bone substitutes do not provide the cellular elements necessary for osteogenesis, and they cannot be considered osteoinductive, but instead are osteoconductive, providing a scaffold for new bone deposition. Currently, significant decreases in clinical probing depth and attachment levels have been reported with bone substitutes when compared to flap debridement surgery alone for periodontal osseous defects. Reported differences among bone substitutes, autogenous grafts, and allograft materials, occur with respect to histologic outcomes. Overall, probing depth reduction and attachment level gains are similar for all bone replacement grafts.     

Changes in the aortic endothelium and plasma von Willebrand factor levels during the onset and progression of insulin-dependent diabetes in BB rats

The superior volume maintenance of membranous over endochondral bone has been shown in several studies and provides the basis for its preferred clinical use as an onlay grafting material in the craniofacial skeleton. The scientific rationale for this seeming embryologic advantage, however, has never been proven. Our hypothesis is that the pattern of onlay bone graft resorption is primarily determined by a graft's micro-architecture (relative cortical and cancellous composition) rather than its embryologic origin (membranous versus endochondral). Twenty-five adult New Zealand, White rabbits were used for this study. Eight animals were killed at 3 weeks, eight animals at 8 weeks, and nine animals at 16 weeks. Three graft types were placed onto each rabbit cranium: cortical bone graft of membranous origin and cortical and cancellous bone graft of endochondral origin. Fluorochrome markers were injected into all living rabbits at 1, 6, and 14 weeks. Microcomputed tomography scanning was performed on all of the bone grafts to determine postsacrifice volumes and to obtain detailed information regarding the bone graft's trabecular architecture. In addition, specimens were examined histologically. Volume analysis showed a statistically greater resorption rate in the cancellous endochondral bone graft than in either the endochondral or membranous cortical bone grafts (p < 0.05) for all time points. In addition there was no significant difference in the resorption rates between the endochondral and membranous cortical bone grafts. A post-test power analysis (alpha = 5 percent) of the volume data comparing the two types of cortical bone grafts showed that a difference in resorption of 8.9 percent would be detected with a 90-percent probability. Previous studies, which have shown a seeming superiority of membranous over endochondral bone grafts, used composite grafts composed of both cortical and cancellous portions. By separating these components, we have shown that cortical bone grafts maintain their volumes significantly better than cancellous bone grafts. In addition, we found no statistical difference in the resorption rates between the two cortical onlay bone grafts of different embryologic origins, a finding that has never been previously published. From our results, we believe cortical bone to be a superior onlay grafting material, independent of its embryologic origin. We believe these results challenge the currently accepted theories of bone graft dynamics and may lead to a change in the way clinicians approach bone graft selections for craniofacial surgery.     

Prognostic factors and therapeutic options of radiotherapy in pediatric brain stem gliomas

BACKGROUND: Calvarial bone graft is often used in reconstructive cranio-facial surgery. As most common three different forms can be distinguished: outer-table bone, full thickness grafts and composite flaps (bone with a periostal or muscular pedicle). PATIENT AND METHOD: An extensive fibrous dysplasia of the frontal region was removed in a 26 years old patient. Reconstruction was carried out with alloplastic material achieving a good esthetic result. Recurrent seroma and occurrence of a fistula demanded removal of the alloplastic material and en-bloc reconstruction of the forehead region was accomplished with a parietal outer-table graft. Within a follow-up time of one year a good esthetic and stable reconstruction has been achieved. CONCLUSION: Split-thickness calvarial bone is still a versatile graft in reconstruction of the forehead region. Although a low rate of side effects in harvesting calvarial bone grafts are in general expected, one has to be aware of dural lesions occuring in the donor site during craniotomy.     

Long-term follow-up of cranial bone graft in dorsal nasal augmentation

A follow-up of 363 cranial bone grafts for nasal reconstruction is presented. The main indications for the surgery were congenital, posttraumatic, or postrhinoplasty deformity. The results were satisfactory in the vast majority of cases. The complications associated with the grafts and with the donor site are discussed, as are the methods to treat and prevent these complications from occurring.     

The viability of cryopreserved onlay cranial bone allografts: a comparative experimental study versus fresh autografts

It is well known that calvarial bone autografts are the bone grafts that are the least reabsorbent and have the best long-term evolution in craniofacial surgery. However, they do have certain limitations: (1) reabsorption results in repeated surgery and the need for new donor areas, (2) a limited amount of autogenous cranial bone is available (due to avoiding areas close to cranial sutures and venous sinuses, and because the temporal bone is very fragile and the cranium has not fully developed in children), and (3) graft extraction increases surgical time and morbidity. Because of this, we present an alternative to calvarial bone autografts: cryopreserved allografts. This paper is an experimental prospective study carried out on sheep with the following goals: (1) to assess the behavior of calvarial onlay bone grafts cryopreserved at -80 degrees C, using fresh autografts implanted under the same conditions as controls; (2) to compare reabsorption percentages statistically over time; and (3) to study qualitatively any histological variations. The results obtained are (1) more reabsorption of allografts when compared to autografts (at 90 days, 21.97% versus 20.21% of grafted volume), although this difference is not statistically significant; (2) a reduction in height in all onlay grafts as a consequence of the loss of the dipl?e; (3) the absence of any type of inflammation caused by a reaction to cryopreserved allografts; and (4) bone substitution performed using frozen allografts is histologically similar to that using fresh autografts.     

Mandibular onlay grafting using prefabricated bone grafts with primary implant placement: an experimental study in minipigs

The aim of this experimental study was to evaluate the use of prefabricated autogenous bone grafts as onlay grafts to the mandible. Excess bone of 10 x 12 x 40 mm was produced inside blocks of pyrolyzed bovine bone under a polylactic membrane coverage on the outside of the mandible in 15 adult G?ttingen minipigs. After 5 months, this bone was harvested and transferred to the premolar region of the mandibular body in 10 animals. Onlay grafts of mandibular bone were used as controls for the transplanted prefabricated grafts. All grafts were fixed by primary placement of one titanium implant each. Five animals served as ungrafted controls. Evaluation was performed after 3 months and 5 months, respectively. Two animals were lost to evaluation, and one scaffold became infected. Eleven of the remaining 12 scaffolds showed sufficient bone ingrowth for grafting. Three months after transplantation, bone volume of the prefabricated grafts was almost completely preserved, with only minimal resorption in the superficial pores of the scaffolds, while the control grafts exhibited partial resorption. The titanium implants, which had been placed at the time of only grafting, exhibited direct bone-implant contact. Five months after grafting, all titanium implants showed complete osseointegration, with direct bone-implant contact. The grafted bone exhibited a significant increase in bone density by appositional bone formation. The control grafts were nearly completely resorbed at that time.     

Allografts in extensive spinal arthrodesis

Surgery of spinal deformities and vertebral tumors often requires extensive arthrodesis, with the difficulty of obtaining sufficient autogenous bone graft (particularly in children and cases of paralytic deformities) and the necessity of a second incision, thus lengthening the operation and eventual increase of the morbidity. We present 52 patients who suffered from vertebral tumours, fractures or spinal deformities and underwent spinal arthrodesis surgery. Femoral head allografts were used as cancellous bone graft to add to the amount obtained from the arthrodesis bed itself (posterior structures). In three occasions, femoral head grafts shaped as a strut were also used as intersomatic bone graft, being implanted via a costotansversectomy. The only complication was the appearance of seromas of spontaneous resorption in the first 15 cases (thereafter repeated cleaning of the bone graft avoided this problem). In our experience, bone grafts facilitate the carrying out of shorter surgical operations but can also avoid having to recourse the further incisions without reducing the possibility of obtaining a successful arthrodesis.     

Reconstruction of the mandible with conventional bone graft: an evaluation

Eighteen patients with bony defects of the mandible had the mandible reconstructed using conventional nonvascularized bone grafts from the iliac crest. After surgery they received radiotherapy for cancer in the oropharynx or oral cavity. This study was carried out over a 10-year period. All patients were followed-up both for their tumour growth and the results of their reconstruction. Four to 10 years after surgery 55.5 per cent were alive and well. Full dental rehabilitation was achieved in 33 percent and 12.5 percent were without dental rehabilitation.     

A comparison of vascularized and nonvascularized bone grafts for reconstruction of mandibular continuity defects

PURPOSE: This study compared vascularized and nonvascularized bone grafts for the reconstruction of segmental defects of the mandible. PATIENTS AND METHODS: The results in 39 patients having vascularized bone grafts (38 fibulas and one iliac crest) and 29 patients having nonvascularized bone grafts (26 iliac crest [22 corticocancellous block grafts, four cancellous bone grafts in a tray] and three rib grafts) for segmental mandibular reconstruction were evaluated in terms of overall success rate, total number of surgeries performed, total blood loss, total number of hospital days, and total number of hours in the operating room. RESULTS: Of 39 vascularized bone grafts, two failed (95% success rate), whereas of 29 nonvascularized bone grafts, seven failed (76% success rate). Failure for the nonvascularized bone grafts was closely correlated to the length of the defect. Nonvascularized bone graft patients underwent an average of one more surgical procedure for total reconstruction than vascularized bone graft patients, including osseointegrated implants. However, vascularized bone graft patients spent a mean of over 14 additional days in the hospital for all of their reconstructive procedures and an additional 3 hours in the operating room as compared with nonvascularized bone graft patients. Blood loss was similar in both groups (1,100 mL). Only 20% to 24% of patients in each treatment group have completed reconstruction to include osseointegrated implants. CONCLUSIONS: The success rate for vascularized bone grafting is high and is the treatment of choice when primary reconstruction is required, when the patient has been previously irradiated, or when simultaneous replacement of soft tissue is required. Vascularized bone grafts are also the treatment of choice for mandibular replacements over 9 cm in length. Nonvascularized bone grafts create a better contour and bone volume for facial esthetics and subsequent implant insertion, and may be the treatment of choice for secondary reconstruction of defects less than 9 cm in length.     

Autologous calvarial and iliac onlay bone grafts in miniature swine

Calvarial bone has been reported to be superior to iliac bone for onlay bone grafting due to decreased resorption. This study evaluated the physical, histologic, and radiographic characteristics of calvarial and corticocancellous iliac onlay bone grafts in nine Pitman-Moore miniature swine at 2 weeks, and at 1-, 2-, 4-, 6-, 7-, 8-, 10-, and 12-month intervals. Compared with iliac grafts, the calvarial onlay grafts had more than a twofold greater radiographic density. Statistical analysis of the mature grafts using the standard of estimated means of the bone graft volumes revealed 85% retention of the calvarial grafts compared with 34% retention of the grafted iliac bone. There was no subjective difference in the rate or degree of revascularization between the two grafted materials.     

A double-blind, randomized, controlled trial of the effects of two eggs per day in moderately hypercholesterolemic and combined hyperlipidemic subjects taught the NCEP step I diet

BACKGROUND: Thirty-three patients with nontuberculous pyogenic thoracic and lumbar vertebral osteomyelitis were treated surgically. Indications for surgery were either progression of disease despite adequate antibiotic therapy, neurologic deficit, or both. The most common initial symptom was back pain. Seven patients had diabetes, seven patients were intravenous drug users, two patients were receiving immunosuppressive therapy, and seven patients had a debilitating disease. Eleven had infections elsewhere in their bodies. Prior to surgery organisms were grown from blood in 10 patients and at surgery in 15 patients. METHODS: Infection was evident on plain films in all patients, and either a CT scan or MRI was obtained in each. The lateral extracavitary approach was used for resection of granulation tissue and infected bone ventral to the dura. Interbody bone grafts were placed in 19 patients, usually when bone resection was extensive. Posterior instrumentation was placed in 17 patients at a second procedure 10 days-2 weeks following initial operation. Intravenous antibiotics were administered for 4-6 weeks following surgery, and solid fusion was obtained in all patients. RESULTS: Neurologic deficit was present in 28 patients prior to surgery and was functionally significant in 18 patients. Of the 11 patients with severe paraparesis, 10 achieved good functional recovery. These patients were able to walk, three with assistance and seven without, and all those who were unable to void regained this ability. CONCLUSIONS: Surgical debridement, interbody fusion, and posterior instrumentation is a safe and effective treatment for vertebral osteomyelitis and is indicated when neurologic deficit or bone destruction progress despite adequate antibiotic therapy.     

Effects of primary bone grafting on facial development in patients with unilateral complete cleft lip and palate

The study is based on an anthropometric assessment of X-ray films obtained in 22 adult males with complete unilateral cleft lip and palate treated during childhood with primary bone grafts and in 32 males with the same type of cleft without bone grafting. In the series with bone grafts was recorded a more marked reduction of maxillary depth associated with a larger retrusion than in the series without bone grafts. This deviation was therapeutically compensated by a larger displacement of the mandible backwards which contributes to the increase of mandibular posterior rotation. This provided the possibility to attain an edge to edge bite. Our results confirmed the unfavourable effects of primary bone grafting on maxillary growth and development.     

A paradigm of experimentally induced mild hyperthyroidism: effects on nitrogen balance, body composition, and energy expenditure in healthy young men

OBJECTIVE: To conceptualize, with fine needle aspiration cytology (FNAC), the early cellular events occurring in and around fresh autogenous and allogenic bone grafts during the first 40 postimplantation days. STUDY DESIGN: Forty-eight cases of bone grafts were studied by FNAC at serial intervals of 10, 20, 30 and 40 postimplantation days. Twenty patients were recipients of autogenous grafts, 16 received 0.6N HCI partially decalcified allogenic bone implants, and 4 received combined autogenous and allogenic bone grafts (included in the allograft group). There were eight control cases of closed fracture shaft femur, which were managed conservatively. RESULTS: The initial cellular responses in autogenous grafts, allografts and controls appear to be a part of the nonspecific reparative process followed by a more specific phase, with a steady increase in relative lymphocyte count from the 20th day onwards. Osteogenesis, as judged by osteoblasts and osteoclasts, was also comparable. CONCLUSION: Partially decalcified allografts appear to be a good substitute for autogenous bone grafts in clinical practice when adequate autogenous material is not available. FNAC is a good technique for studying bone graft responses without interfering with graft uptake. It is helpful in the early detection of subclinical infection or any other pathology at the graft site.     

Contents of total and protein-bound carbohydrates are low in leukemic leukocytes from patients with acute myelogenous leukemia

The successful approach to the failed knee with bone deficiency is dependent upon thorough planning prior to surgery in order to have the resources available in terms of adequate bone allograft and suitable revision implants. The approximate size of bone stock deficiency can be calculated from preoperative radiographs and similarly ligamentous incompetence can often be diagnosed clinically prior to surgery. Smaller defects of up to 1 to 1.5 cm in depth and localized in the main to a single side of the tibial plateau or to a single femoral condyle can be dealt with using smaller grafts that may be local autograft or allograft, or modular wedges. Larger tibial defects can be compensated for using conventional revision systems by thicker polyethylene and augmented baseplates, but once the flexion-extension gap reaches approximately 40 mm this is no longer possible and structural graft or customized componentry becomes necessary. Femoral defects larger than about 1 cm that cannot be made up by augments necessitate grafting. The need to use a large proximal tibial allograft also may dictate the operative approach used to expose the joint, especially in the situation of a multiply-operated tight knee. In such cases the use of a quadriceps turndown may be more advisable than the use of a tibial tubercle osteotomy as the osteotomy may well not have an adequate bed to heal to following the reconstruction. Several series have reported cases of patellar tendon avulsion and the clinical results following this complication usually are not satisfactory. Preoperatively it is important to identify, if possible, the case that is likely to require a more extended approach because of a tight soft tissue envelope. The reports of results of series of revision total knee arthroplasty in the setting of significant bone loss are at present confined to short-term followup. The clinical results of these series are satisfactory at this early point in time, but decision regarding the durability of reconstructions requiring major structural allografting awaits longer-term study. Of concern is the devastating complication of infection following such revision surgery, the risk of which is amplified in the setting of prior infection. In addition, the long-term viability of major structural grafts in the setting of loading is uncertain as the risk of graft collapse in the process of incorporation is not known. Notwithstanding these concerns, major grafting is sometimes the only recourse to achieve satisfactory revision of a failed arthroplasty. The use of such major grafts is therefore cautiously supported and because of the risks inherent in such surgery we believe that such surgery should be carried out in the setting of specialist interest units.     

Intracellular distribution of phospholipase C gamma 1 in cell lines with different levels of transformation

PURPOSE OF THE STUDY: To assess after 83 months of follow-up, the results of 19 femoral revisions carried out according to an original method combining a cemented stem and bone reconstruction by means of impacted-morcelized bone allograft protected by a titanium mesh. MATERIALS: Twenty hips (18 patients mean aged 58 at surgery) were included between 1986 and 1991. Five hips had a least one previous prosthetic revision, one hip was revised because of septic loosening. No patient was lost for follow-up, but two had died during the follow-up period: one patient died one month after surgery was excluded, one other died 7 years after the index procedure and was included with his last hip rating. Loss of femoral bone stock was severe according to the SOFCOT four stage rating system: 2 femurs were grade II, 14 grade III, and 3 grade IV. Femoral stem migration was assessed with landmarks recommended by Walker. All the measurements were performed with a digitizer (OrthoGraphics). METHODS: All the procedures were carried out through a posterolateral approach, augmented by 4 trochanteric osteotomies and 5 distal femoral windows. After prosthesis and cement removal, a bone plug was placed into the medullary canal. Then, cancelous bone morcelized allografts were impacted in the femoral defects through the medullary canal. A titanium mesh cylinder was placed into the femur to separate the graft from the cement introduced later to obtain fixation of the revision stem. The stem was extended about 5 centimeters over the distal edge of the grafts in order to bridge the femoral defects. The mesh was extended only in front of the grafts and was used to protect them from excessive cement penetration. RESULTS: Functional improvement was noticeable since the Merle d'Aubigné Hip score improved from 9.8 to 16.3 at follow-up. The pain score improved from 2.1 to 5.5 and walking score from 2.3 to 5. Adverse effects occurred during the first cases and were related to cement removal: 3 greater trochanter fractures, 5 distal femoral perforations and 2 non displaced femoral shaft fractures. The septic revision had recurrence of infection associated with radiolucent lines > 2 millimeters and the only one graft resorption. One trochanteric non-union was observed but no prosthetic dislocation. Only one femoral stem migration (4.4 millimeters) was detected without any other radiographic features of loosening after 9 years of follow-up. This stem was considered as loosed, but was not revised because of few clinical symptoms. Only 2 radiolucent lines less than 2 millimeters at the bone cement interface in Gruen's zones 3 to 5. Likewise, no radiographic feature of stress-shielding was observed. On follow-up X-rays, 3 hips had corticalisation of the grafts, and 12 hips demonstrated normal cancelous trabeculations in the grafts. CONCLUSION: Satisfactory functional and radiographic results were obtained with this method after 5 to 10 years of follow-up instead of severe preoperative femoral bone stock impairement. Likewise, we observed only one recurrence of loosening diagnosed with the help of digitized X-ray examination. Only one significant (> 3.5 mm) femoral stem migration was detected. Radiographic features of femoral reconstruction were observed but without histologic proof of graft integration. This method uses a longer stem than the "Exeter", but avoids a high rate of femoral stem migration and appears compatible with femoral bone reconstruction.