Evaluation of postoperative changes in vascularized iliac bone grafts used for mandibular reconstruction

Vascularized iliac bone grafts are used for mandibular reconstruction, but the factors affecting graft maintenance are unknown. This study explored the postsurgical changes in vascularized iliac bone grafts in patients who had undergone mandibular reconstruction after segmental resection. The study involved 24 patients (16 men and eight women) with oral tumours or osteoradionecrosis. Thirteen patients required bare bone grafting (BBG) and 11 patients required reconstruction with soft tissue coverage (six with a skin paddle and five with direct closure). The bone graft maintenance rate (with regard to the height of the centre of the graft) was calculated immediately after surgery and at 3, 6, 12, 24, and 36 months after surgery. The maintenance rate was significantly lower in the BBG group than in the soft tissue coverage group at 3, 6, 12, 24, and 36 months, and in those who were fitted with dentures compared to those who were not at 6, 12, 24, and 36 months. Local infection also influenced the maintenance rate, but not significantly so. These findings indicate that the reconstruction technique and denture use can affect the bone graft maintenance rate after mandibular reconstruction with vascularized iliac bone grafts.     

Tissue reaction around miniplates used for the fixation of vascularized iliac crest bone grafts

Material/Method. In six miniature pigs revascularized autologous iliac crest bone grafts were fixed with two 2.0 mm titanium miniplates to a defined defect in the angle of the mandible. Tissue reaction around the implants was examined histologically and histomorphometrically at 2, 4, and 8 weeks after surgery.Results. According to the evaluation of fluorescence microradiography, the cortical and medullary circulation and healing processes of bone in the vicinity of the implanted material were not disturbed after 2 weeks. At 4 weeks after surgery osseous healing occurred at the mandibula/graft interface. The histomorphometric results for the calculated percentage of direct bone/screw contact at 2 weeks were 24% with the grafted bone and 53% with the mandible. Intensive bone formation was observed in all parts of the graft by 4 weeks. The results of direct bone/screw contact at 4 weeks were 56% and 64% and at 8 weeks 75% and 77% for the grafted and the mandibular bone, respectively.Conclusion. With 2.0 mm titanium miniplates used in the animal model, stable osteosynthesis and osseous healing was evident after 8 weeks of surgery. In addition, intensive remodeling of the transplanted bone without signs of creeping substitution was noted, and the bone/screw contact of the miniplate system increased with time.     

ITI种植体即刻植入血管化髂骨修复下颌骨缺损12例分析

目的:种植体植入血管化髂骨修复下颌骨缺损已成为一种常规治疗方法。本研究对一组ITI种植体即刻植入血管化髂骨后的效果进行评价。方法:对2000～2004年间12例患者共36枚ITI种植体植入血管化髂骨的情况进行研究。髂骨瓣移植完成即刻种植体植入,3～5个月愈合期后进行修复负载。结果:种植体植入髂骨后初期稳定性良好,经1年观察,垂直骨吸收<1m m,进入稳定状态。在观察期间无种植体失败。结论:血管化髂骨是下颌骨缺损修复安全的种植床。种植体支持的固定义齿和覆盖义齿修复,是下颌骨缺损可靠的修复方法。     

种植联合血管化髂骨移植重建14例下颌骨缺损的长期疗效观察

目的: 通过临床及影像学方法,评估种植联合血管化髂骨移植重建下颌骨缺损的长期疗效。方法: 对上海交通大学医学院附属第九人民医院1995—2005年收治的14例患者47颗植入血管化髂骨的种植体进行随访,其中10例30颗种植体为下颌骨血管化髂骨重建术中同期植入,4例17颗种植体为术后二期植入,上部结构均采用种植支持式固定义齿修复。评估分析种植体15年累积生存率及修复体生存率,修复完成后5年及10年分别进行临床评价。采用SPSS 26.0软件包对数据进行统计学分析。结果: 种植体均未发生愈合期内失败。种植体10年、15年累积生存率分别为90.44%和86.67%,修复体15年累积生存率为78.32%。种植体5年及10年边缘骨吸收分别为（2.08±0.27）mm和（4.22±0.48）mm,两者有显著差异（P<0.0001）。生物学并发症主要为种植体周围炎及软组织增生,机械并发症主要为修复体磨耗。结论: 种植联合血管化髂骨移植重建下颌骨缺损的长期疗效较为稳定,是下颌骨缺损重建的有效方法;但种植体周围炎发生率较高,维护种植体周围软、硬组织的稳定是种植体远期疗效的重要保证。     

An experimental study of healing around hydroxylapatite implants installed with autogenous iliac bone grafts for jaw reconstruction.

The purpose of this study was to evaluate the use of hydroxylapatite implants (HA) with autogenous bone grafts for jaw reconstruction. After autogenous iliac bone grafts were transplanted to 36 rabbit mandibles, an HA implant was installed into the graft immediately (IM group), or 90 days (90D group), or 180 days (180D group) later. The animals were killed 7, 14, 30, 60, 90, and 180 days after the HA implant placement. The healing process was examined histologically, and histomorphometric measurements were made with a computer-based image analyzer to quantify the percentage of HA-bone bonding and trabecular bone in the medullary cavity. In the IM group, the HA-bone bonding tended to be deterred by fibrous tissue, and the rate of HA-bone bonding (BBSR) was less than that of the other groups. The trabecular bone around the implants tended to decrease after 30 days in all groups. However, the average of the trabecular bone specific volume (tVsp) in the 90D group was about 10% higher than that in the other groups. From these results, it is concluded that in clinical use of HA-coated dental implants with autogenous bone grafts, the time of installation should not be immediately after the bone graft, but when there is sufficient newly formed trabecular bone to enhance HA-bone bonding.     

在移植骨上延期种植的实验研究

目的论证冷冻自体下颌骨复合髂骨移植后延期种植的可行性。方法16只成年雄性杂种狗，制备下颌骨双侧骨缺损，左侧行冷冻自体下颌骨骨块的原位再植并结合髂骨松质骨移植，即复合移植组（composite transplantation group，CTG），右侧缺损行自体髂骨块移植即髂骨移植组（iliac transplantation group，ITG），术后3个月分别在两类骨块上植入IMZ TPS种植体，种植体植入后3、6、9、12周分别处死4只动物取材，采用数字化X线片对种植体与颌骨结合界面进行灰度定量分析，组织学观察种植体．骨结合情况。结果各期种植体周围均未见吸收性骨质密度减低影像。骨一种植体界面灰度定量分析显示，种植体植入两类移植骨3、6和9周时，其界面骨质密度改变差别明显，复合移植组明显优于髂骨移植组；种植体植入12周时，两组界面骨质已无明显差别，两类移植骨均与种植体有良好的骨结合，其骨愈合方式基本相同。结论冷冻自体下颌骨复合移植修复下颌骨缺损并延期植入牙种植体后，二者可形成良好的骨结合。     

A comparative investigation on autologous mandibular and iliac crest bone grafts. An experimental study in sheep

Nine Friesian sheep (age 1.5-2 years) were used to evaluate the quality of bone repair in artificial cleft-like maxillary defects repaired with autologous bone grafts of embryologically different origin. After bilateral extraction of the upper first deciduous molar the tooth socket was enlarged resulting in an open connection between the oral and nasal cavities. In the same session a graft, obtained from the iliac crest, was implanted in one of the two bilateral maxillary defects and on the opposite side a graft, obtained from the mandible, was inserted. During the experiment, serial radiographs were taken. After six months the sheep were sacrificed and the bone of the grafted areas was submitted to histological and histomorphometric investigation. Comparing both areas, it appeared that the quality of bone remodelling and alveolar reconstruction was independent of the origin of the grafts.     

A new technique for obtaining iliac bone grafts

A new method for obtaining corticocancellous bone grafts for use in orthognathic and facial reconstructive surgery is presented. By raising an osteoperiosteal flap from the crest of the ilium and removing a medial corticocancellous bone block, graft site morbidity is minimized, the patient's return to ambulatory status is hastened, and an excellent graft is procured.     

Three-phase bone scintigraphy and viability of vascularized bone grafts for mandibular reconstruction

Three-phase bone scintigraphy was undertaken to check the anastomotic patency and monitor the viability of vascularized bone grafts. Ten consecutive patients who underwent vascularized bone grafting of the mandible were reviewed. A successful clinical outcome was achieved in 8 patients. The graft failed in 2 patients. In this series, 3-phase bone scintigraphy of radiolabeled (99m)Tc-methylene-diphosphonate was performed at 7 days, and at 1, 3, 6, and 12 months after reconstruction. Assessments made using 3-phase bone images were compared with the clinical findings. The clinical outcome of the cases presented in our series correlated extremely well with 3-phase bone images. Three-phase bone scintigraphy is a useful method for the assessment of patency and viability of vascularized bone grafts. The use of this method can be very helpful in assessing the anastomotic patency and viability of a graft which for clinical reasons is suspected of being non-viable.     

Resorption of microsurgically vascularized bone grafts after augmentation of the mandible.

Vascularized bone grafts taken from the iliac crest to augment the extremely atrophied mandible are valued for their ability to maintain their contour. Reliable data on long-term performance, however, is not yet available. The purpose of this study was to investigate the long-term results of this method, evaluating the radiological documentation (lateral cephalograms, orthopantomograms) of six patients. The mean follow-up period was 7.3 years. Dental implants were not inserted into the bone grafts. The average increase in ridge height immediately after surgery was 17.8 mm in the symphyseal area, 17.1 mm above the mental foramen and 13.9 mm in the molar region. In the first postoperative year, the average vertical loss was 3.0 mm in the symphyseal, 2.0 mm in the premolar and 2.9 mm in the molar regions. After that the mean yearly rate of vertical resorption dropped to 0.24 mm in the symphyseal, 0.27 mm in the premolar and 0.34 mm in the molar regions, which corresponded to the physiological loss in ridge height due to aging. The fact that graft resorption was so slight portends a good long-term prognosis with this procedure. However, indication is restricted by the high operative burden for the patient and by the availability of alternative rehabilitation methods.     

A comparison of parietal and iliac crest bone grafts for orbital reconstruction.

PURPOSE: This study evaluated the results of cranial (membranous) versus iliac crest (endochondral) bone grafts as implants to correct post-traumatic globe malposition and/or diplopia. PATIENTS AND METHODS: Twenty-two patients underwent 25 orbital reconstructions with bone for enophthalmos, hypophthalmos, and diplopia after trauma to the orbit. Inclusion criteria consisted of at least 4 months postsurgical follow-up, pre- and postsurgical quantitative orbital measurements, photographic documentation, and complete medical records regarding inpatient and outpatient data. RESULTS: Nine cranial bone grafts and 16 iliac crest grafts were placed. Ages were similar in both groups. The average follow-up was 24 months for the cranial graft group (range, 4 to 54 months) and 18 months for the iliac crest graft group (range, 4 to 51 months). Preoperative enophthalmos averaged 4.11 and 5.06 mm in the cranial and iliac crest groups, respectively, and postoperatively the measurements were 1.78 and 1.37 mm, respectively. Changes in hypophthalmos generally reflected changes in the enophthalmos correction. In 10 patients diplopia was corrected by the procedure. There was a statistically significant change in the enophthalmos of patients when comparing pre- and postoperative status, but no statistically significant difference between the results of the cranial and iliac crest graft groups. CONCLUSION: There is no difference in the ability of cranial and iliac crest bone grafts to correct post-traumatic enophthalmos.     

Clinical evaluation of vascularized bone grafts and osseointegrated implants

We evaluated mandibular rehabilitation using vascularized bone graft and osseointegrated implants. Questionnaires were used to evaluate the masticatory function, and we measured the occlusal force in each patient. In addition, we measured the height of grafted bone to assess the possible relationship between masticatory rehabilitation and the change in bony height. Five of 13 patients showed over 12.0% increase in bony height after superstructure fabrication. Most of the patients who underwent tongue resection scored low points on the questionnaire. Also, most patients with resection, including resection of the angles of the mandible, showed a lower occlusal force than those without.     

The use of vascularized bone grafts in osseointegration. A clinical report

This clinical report presented the concept of a vascularized bone graft for mandibular reconstruction coupled with osseointegration to achieve a superior rehabilitative result. The potential use of these two modalities enables the reconstructive team to restore functional and esthetic levels previously not possible after radical surgery. The application of this technique is not limited to cancer surgery patients, but may be advisable for patients requiring reconstruction of mandibular discontinuity.     

Comparative study on healing process between vascularized and non-vascularized autogenous bone grafts]

This study made a histological comparison (light microscope and transmission electron microscope) between vascularized bone graft (VBG) and non-vascularized bone graft (NVBG) in mandible of dog.The study showed:the healing process of VBG was the same as that of bone fracture.The "creeping substitution" process of NVBG was imbued with the inflammation induced by dead bone.There was no significat difference on the bone union between VBG and NVBG perhaps for the recipient region was better vascularized.     

A novel implantation model for evaluation of bone healing response to dental implants: the goat iliac crest

Objectives: Despite the availability of numerous animal models for testing the biological performance of dental and orthopedic implants, the selection of a suitable model is complex. This paper presents a new model for objective and standardized evaluation of bone responses to implants using the iliac crest in goats. Material and methods: The feasibility of the iliac crest model regarding anatomy and implant positioning was determined using two cadaveric specimens and the bone structure was evaluated and compared with that of the goat femoral condyle. Additionally, the validity of the model was tested by performing an in vivo study. Results: By means of a rather simple, safe, fast and reproducible surgical procedure, the iliac crest in goats could be approached and allowed the implantation of maximally five dental implants per iliac crest. Because of the bilateral implantation possibility, statistical comparisons between groups on either side of the goat could be performed, resulting in a high statistical power, and hence a reduction in the number of animals required to obtain significant data. Conclusions: In terms of surgical approach, anatomy and implant positioning, the iliac crest is the preferred model over the femoral condyle model. The iliac crest implantation model is suitable for evaluation of the osteogenic response to bone implant materials and represents a justified and deliberate alternative to the already existing animal models. To cite this article:
Schouten C, Meijer GJ, van den Beucken JJJP, Spauwen PHM, Jansen JA. A novel implantation model for evaluation of bone healing response to dental implants: the goat iliac crest.
Clin. Oral Impl. Res. 21 , 2010; 414–423.
doi: 10.1111/j.1600‐0501.2009.01872.x     

Radiologic appraisal of healing after iliac crest bone grafts

Radiographic changes were observed in 45 patients who had undergone iliac bone grafting with either metal or wire fixation after resection of the mandible. Changes were generally not observed during the first month after surgery. Bony resorption was seen during the second or third month. Osteogenesis commenced at any stage, but was usually radiographically evident by 3 to 6 months. Union was not radiographically evident in most cases until more than 6 months had elapsed after surgery. For follow up, plain film radiographs 4 to 6 months after surgery are recommended in patients who receive bone grafts.     

非血管化髂骨和下颌骨与钛种植体结合的比较研究

目的 :研究非血管化髂骨和下颌骨与钛种植体结合的组织学特点。方法 :12只杂种犬随机分为 6组。切取 15mm× 5mm的下颌骨骨质 ,将骨块移植于对侧下颌骨人工骨缺损区 ,然后切取同样大小的髂骨骨块 ,移植于下颌骨骨缺损区 ,同时植入 2枚钛种植体 ,用种植体固定骨块。术后不同时间点取材 ,组织学观察。结果 :髂骨移植后早期以溶解坏死为主 ,6周时开始重建 ,种植体为混合界面 ;12周时改建基本完成 ,种植体形成骨结合。而下颌骨移植后早期移植骨吸收不明显 ,只是哈佛氏管扩大 ,与种植体界面间未见新骨形成 ;12周时移植骨内出现新生骨 ,骨吸收停止 ,种植体为混合界面 ,界面有不成熟的新生骨沉积 ,新骨与原骨结合不紧。 18周 ,种植体形成骨结合。 2 4周 ,移植的髂骨和下颌骨与骨床均融为一体 ,下颌骨与髂骨相比整体致密。结论 :髂骨与下颌骨移植后的修复过程及它们与钛种植体的骨结合过程不同 ,但均能形成骨性结合。下颌骨与种植体形成骨结合的时间比髂骨长     

A prospective study of trephined bone grafts of the tibial shaft and iliac crest

Autogenous cancellous bone grafting is a common procedure in maxillofacial surgery. Open harvesting usually results in a long scar and considerable morbidity, but harvesting using a trephine can be done through a smaller scar with minimal morbidity. The commonly used anatomical areas for trephine harvesting are the iliac crest and the tibia] shaft. A prospective study was carried out in 30 patients to compare the technique and the morbidity as perceived by patients using a visual analogue scale (VAS) and by an independent observer. The surgical anatomy and techniques are described. The results show no significant difference between the two groups, but the tibial trephine procedure is easier, quicker, and causes less blood loss. The total scores for pain and difficulty in walking were much less for tibial than that for the iliac grafts.     

Rehabilitation of patients with congenital unrepaired cleft palate defects using free iliac crest bone grafts and dental implants

PURPOSE: To rehabilitate the mastication and speech of edentulous congenital cleft lip and palate patients with the use of endosseous implants in conjunction with bone augmentation. MATERIALS AND METHODS: Between 1992 and 1999, 6 partially and 4 completely edentulous adult patients with complex cleft palate defects were treated. Six patients had large, unrepaired defects of the hard and soft palate, whereas the other 4 had residual oronasal fistulas after failed palatoplasty and bone grafting. In 8 patients, free inlay-antral and simultaneous lateral-onlay bone grafts (3 patients) were obtained from the iliac crest, and dental implants were placed secondarily. In the other 2 patients, the implants were placed without grafting in recent extraction sites. Rigid bars with extensions over the defects were used to support obturator prostheses (n = 7), or patients were provided with fixed implant-supported prostheses (n = 3). In all, 50 cylindric, screw-type dental implants were placed and followed up for 1 to 8 years (mean, 5 years). RESULTS: Six implants were regarded as early failures and 1 was lost during the first year of loading; 1 patient lost all 5 implants. The cumulative success rate at 5 years was 85.7%. DISCUSSION AND CONCLUSION: All 9 successfully rehabilitated patients reported a remarkable functional and psychologic improvement after the treatment. The described treatment protocol also seemed to be effective for correcting velopharyngeal insufficiency in patients using an obturator prosthesis.