## 4 Discussion
The reconstruction plates are then manually bent on the operating table depending upon the defect created. Following the presented approach and protocol, the mean linear discrepancy between the planned and post-operative position was 1.43 \(\pm\) 1 mm in category I, 1.72 \(\pm\) 1.29 mm in category II and 4.92 \(\pm\) 3.8 mm in category III. The values in category I and II are in line with the accuracy studies in previous similar studies, if not better [7,24,25,26]. Moreover, the comparison of accuracy result among the category I and II did not show significant differences in the mean discrepancies between the virtual plan and the result. This provides a reliable base to use the proposed algorithm in the mentioned clinical scenarios. However, we observed that the linear discrepancy values in category III seemed a bit at larger side (i.e., 4.92 \(\pm\) 3.80 mm). Category I and II also showed significant difference in the mean discrepancies with category III. Looking at the defect types in this category, two patients had LCL defect and one had LC defect. The difference in discrepancy values between relatively smaller mandibular defects (L/LC) and larger defects (LCL) was also studied. The former group had nine patients from categories I/II/III whereas the latter group had two patients under category III. It was an interesting finding to note that the mean discrepancy value in L/LC defects was 1.99 \(\pm\) 1.34 mm and that in LCL defects was 5.98 \(\pm\) 4 mm; the difference being statistically significant. This somehow leads to an observation that the accuracy difference of manual plate bending protocol presented here might not be implicated to categorical differences but to defect size (i.e., huge bilateral mandibular defects (ramus/condyle to ramus/condyle)) showed lesser accuracy results as compared to smaller defects (L/LC). Several factors could be attributed to the decreased accuracy results in LCL defect. Firstly, angle to angle or condyle to condyle mandible reconstruction plate is not commonly available. Thus, two mandible reconstruction plates were assembled for reconstruction of larger defect and this kind of assembly can easily lead to the loss of accuracy. Secondly, the small residual parts comprising of bilateral condyle or ramus cannot be stabilized easily to reconstruction plate which can also lead to the inaccuracy in reconstruction. Thirdly, it would also be worthwhile to understand that due to severe scarring and contracture, the soft tissue will not react predictably to the underlying skeletal reconstruction as it would seem in primary cases. Nevertheless, the method of patient-specific manual plate bending would still be justified in those cases where patient-specific 3D printed plate options are not available or affordable, since it certainly avoids subjective guesswork in plate contouring. The two patients with LCL defects are still satisfied with the outcome of reconstruction since they finally received a chin in place of \"[PERSON]\" deformity. A number of studies have attempted to devise mandibular reconstruction protocol using CAD/CAM technology and evaluated the accuracy of plan as well [7,24]. A study by [PERSON] and team found a significant reduction in surgical time, significant change in mean values of selected bony landmarks when comparing computer assisted designs and rapid prototype modelling with conventional manual methods. Comparison of post-operative mandibles with virtual plans showed a mean deviation of 2.40 \(\pm\) 2.06 mm in fibular lengths [27]. In 2016, [PERSON] et al. too evaluated the accuracy of computer assisted mandibular reconstruction with free fibula flap in 8 patients versus 14 patients with conventional manual intervention. Their results showed a deviation in fibula length segment of 1.34 \(\pm\) 1.09 and angular deviation of 2.29 \(\pm\) 1.19 degrees.