Hydroxyapatite/collagen block with platelet rich plasma in temporomandibular joint ankylosis: a pilot study in children and adolescents

The aim of this study was to evaluate the feasibility of using preshaped hydroxyapatite/collagen condyles as carriers for platelet-rich plasma after gap arthroplasty in patients with temporomandibular ankylosis, to assess the aesthetic and functional outcomes, and to find out if neocondylar regeneration was possible. We studied 19 patients with temporomandibular joint ankylosis (25 joints), in whom preshaped hydroxyapatite/collagen condyles with platelet-rich plasma were fixed to the ramus with a titanium miniplate, and temporal fascia was placed in between. We evaluated the type of ankylosis, mouth opening before and after operation, deviation on mouth opening, lateral excursion, protrusion, postoperative anterior open bite, radiographic assessment, and complications. All patients showed appreciable improvements in mouth opening and excursion of the jaw. There were a few complications such as mild fever, and temporary involvement of the facial nerve, which improved with time. No open bite or recurrence was reported during the 18 months’ follow up. Radiographic evaluation at 3 months showed a less opaque condyle, but the opacity at 18 months was more defined, suggesting a newly formed condyle. A preshaped hydroxyapatite/collagen condyle with platelet-rich plasma improves both aesthetics and function. However, a long term study is required to follow the growth patterns to see if the patients develop any facial deformity as they grow.     

Dosimetric Comparison and Feasibility of Simultaneous Integrated Boost (SIB) in Treatment of Malignant Gliomas Using Intensity Modulated Radiotherapy (IMRT) or Volumetric Modulated Arc Therapy (VMAT)

Objective: To evaluate the dosimetric parameters of Simultaneous Integrated Boost in the treatment of malignantgliomas and compare the SIB plans of VMAT and IMRT. Methodology: CT and MRI of 28 patients were used forgenerating SIB plans with VMAT and IMRT. A dose of 2Gy per fraction was prescribed to the CPTV and 2.4Gy tothe GPTV for a total of 25 fractions. The plans were accepted only if they met the set of planning objectives definedin the protocol. Results: We could achieve the planning objectives in all the SIB plans. Although GPTV coverage wasstatistically better in VMAT (98.67% vs 98.19% ;p=0.024) the difference is not clinically meaningful. The conformityindex for GPTV was higher in IMRT (0.83 vs 0.76; p=0.001). The coverage of CPTV was better in IMRT(97.88% vs 96.87%; p=0.021). But the conformity index of CPTVannulus was higher in VMAT (0.72 vs 0.67; p=0.01).There was no difference in homogeneity index of GPTV and CPTV annulus between the plans. The mean dose receivedby normal brain was higher in IMRT (28Gy vs 24.2Gy; p<0.001). Ipsilateral optic nerve has received lesser Dmax inIMRT (44.2Gy vs 46.95Gy; p=0.02). No difference was seen in Dmax of brainstem, optic chiasm, contralateral opticnerve. The treatment times and monitor units were significantly less in VMAT. Conclusion: SIB is dosimetricallyfeasible for hypofractionation in malignant gliomas using IMRT and VMAT. IMRT plans had better boost conformity,lower ipsilateral optic nerve and brainstem maximum doses compared to VMAT. Whereas, VMAT had better coverage,better overall PTV conformity, lower normal brain mean dose, lower monitor units and lesser treatment times. Althoughplanning of VMAT is cumbersome and time consuming, the advantage of reducing treatment time is beneficial tothe patients’ comfort and better managing of patient load in high volume centres.