Discussion
avascular iliac crest grafts, postoperative impairment of the leg, neurosensory deficits, hypesthesia, abduction, peripheral cutaneous nerves
AIDS, CREST
In this study the extent of donor site morbidity in patients receiving CAD/CAM driven reconstruction of the mandible using DCIA grafts was documented. A correlation between the volume of the raised DCIA graft and postoperative use of walking aids and impairment in daily life activities could be found. Moreover, the incision length correlated with the occurrence of neurosensory deficits of the iliohypogastric nerve. The severity of detected neurosensory deficits correlated with the length of the skin incision: anesthesia of peripheral cutaneous nerves was associated with long skin incisions (280 ± 30.0 mm), whereas patients with hypesthesia and normal neurosensory function had shorter skin incisions (245 ± 10.1 mm and 216 ± 27.7 mm respectively). These results confirm that surgery should be performed as minimally invasive as possible to reduce postoperative donor-site morbidity.Liu et al. found a slightly smaller incision lengths of 186 mm in mean in a study group of CAD/CAM treated patients, [ROM of the hip joint of both legs was investigated during physical examination to quantify the impairment induced by surgery. Flexion and internal rotation were decreased significantly (-10.0° ± 14.9° and − 5.0° ± 5.7 respectively) in comparison to the unaffected leg, while other directions of motion were hardly affected after graft harvesting (Table ANOVA was used to investigate further relations of ROM with patient-specific factors (Table Investigation of muscle strength equally showed that the performed surgery using CAD/CAM impairs functionality on the operated leg. Especially flexion (60% of patients), abduction (40% of patients) and internal rotation (27% of patients) were weaker in comparison to the opposite leg (Table In the last 2 years, three systematic reviews were published summarizing the findings regarding donor-site morbidity after head and neck reconstruction of the last 20 years [Katz et al. performed a retrospective chart review of DCIA graft patients and could acquire information about the graft volume in 65% of the investigated cases. A mean graft volume of 8.4 ± 6.9 cmGhassemi et al. performed a prospective interview with a mixed study group receiving vascular and avascular iliac crest grafts without using CAD/CAM techniques [As CAD/CAM techniques have only been part of the clinical routine for approximately ten years, just one other study (Liu et al.) reports of donor-site morbidity in a study population, in which CAD/CAM was used consistently for DCIA graft harvesting [Investigations regarding neurosensory deficits of the pelvis after conventional iliac crest harvesting have been conducted previously [The localizations of nerve alterations most frequently stated in literature (iliohypogastric nerve and lateral cutaneous nerve of thigh) are consistent with the findings of this study [In general, the small sample size of this study (n = 15) obliges cautious interpretation of the presented results. Anatomical or functional peculiarities of our specific study group may affect statistical analysis, which makes generalizability of our results questionable. Pre- and postoperative CT- or MR-data of the donor sites should be used in future studies to enable a more objective evaluation of the anatomical and functional changes. In fact, it would be useful to compare the results with a control group consisting of conventionally operated patients. Since the advantages of CAD/CAM technology and the associated virtual planning are undeniable, it was considered unethical to conduct a case–control study. Instead, a comparison with existing literature reports on conventionally treated patients was conducted. Nevertheless, advanced investigations with larger study groups may be necessary to reveal the true effect of CAD/CAM driven DCIA graft harvesting on postoperative impairment of the leg.