Preservation of the subvalvular apparatus during mitral valve replacement of rheumatic valves does not affect long-term survival.

OBJECTIVES: The importance of preservation of the subvalvular apparatus (PSVA) during mitral valve replacement (MVR) in non-rheumatic mitral valves is well recognized. Our aim was to analyse the impact of PSVA in MVR for rheumatic valves on long-term survival. METHODS: From January 1992 to December 2012, 605 consecutive patients with rheumatic mitral valve disease were submitted to MVR. PSVA (limited to the posterior leaflet) was achieved in 224 (37.7%) patients. Follow-up was 4259 patient-years, and complete for 97% of the patients. Propensity score analysis was introduced to reduce selection bias. RESULTS: Patients with PSVA were slightly older (61.9 vs 59.8 years, P = 0.014), with lower incidence of calcification (54.9 vs 63.0%, P = 0.05), pure mitral stenosis (29.9 vs 38.9%, P = 0.014) and history of rheumatic fever (44.6 vs 53.9%, P = 0.028). Mechanical prostheses were more frequently implanted in the Non-PSVA group (75.1 vs 65.6%, P = 0.013). Thirty-day mortality was 1.1%. Late survival rates at 5, 10 and 18 years were 86.6 ± 2.0, 70.8 ± 3.2 and 48.0 ± 5.1%, respectively, with no difference between groups. Both groups had compromised late survival when compared with the general population (age and gender matched, P < 0.001). Only age, large left atrium, pulmonary hypertension and 'pure' MR appeared as independent predictors for late mortality. There was no difference regarding adverse valve-related events between groups. CONCLUSIONS: Patients submitted to MVR for rheumatic mitral valve disease have a poor prognosis, independently of having the subvalvular apparatus preserved. PSVA did not improve late survival in this setting.

Periodontal impact of surgically induced dental lesions in mandibular osteodistraction: an animal study.

AIM: The objective of the study was to evaluate the impact of dental lesions on the periodontium, in a canine model of mandibular osteodistraction. MATERIAL AND METHODS: In six adult male Beagle dogs, an osteotomy was made between the right second lateral incisor and canine, and a distraction device placed. The roots adjacent to the osteotomy were deliberately damaged by the reciprocating saw and chisel, with preservation of the attached gingiva. The osteodistraction protocol used was: latency of 7 days, rate of distraction 1mm per day, and rhythm once a day for 5 days. Vital staining was carried out with tetracycline, Xylenol Orange and Calcein Green. The dogs were sacrificed after 12 weeks of consolidation and the specimens were evaluated with light microscopy (native, polarized light, fluorescence, and after toluidin blue staining). RESULTS: The periodontal ligament (PDL) regeneration was observed in the 2500 slices examined. Cementum and dentine lesions were repaired by cellular cementum. Loose dentine and cementum-dentine fragments were embedded in regenerated PDL and their surface repaired by cementum. By means of light microscopic examination and within the limited observation time, no degenerative pulpal changes were found, when the pulp canal was not entered. Extensive pulp exposure and destruction resulted in ingrowth of the PDL and bone-like tissue. In that case, cellular cementum also lined the dentine surface of the pulp canal. CONCLUSION: Although there was an extensive reparative response to the para-pulpal lesions, none of the changes observed showed evidence of a loss of functional integrity of the periodontium at the distraction site. The fate of the tooth with exposed pulp canal remains uncertain.

Morbidity related to transmandibular distraction osteogenesis for patients with developmental deformities.

INTRODUCTION: The aim of this retrospective observational case series study was to determine the morbidity of transmandibular Distraction Osteogenesis (DO) using a bone-borne distraction device to adapt the surgical protocol and improve hardware design. PATIENTS AND METHODS: The treatment of 23 consecutive, non-syndromic patients who underwent transverse mandibular DO after a midline symphyseal osteotomy with the TransMandibular Distractor (TMD ) was evaluated. The follow-up period lasted at least 1 year after the end of the contention period. Treatments were analysed according to the morphological and functional Success Criteria (SC) for Craniofacial Distraction Osteogenesis (CFDO) for patients with developmental dentofacial malformations established by the steering group of European Collaboration on Cranial Facial Anomalies (EUROCRAN). RESULTS: Appropriate distraction was obtained in 22 of the 23 patients. One patient had irreversible dentition damage, consisting of an inadvertent apical section. All other SC for CFDO were fulfilled 100% at 1 year follow-up. Seven patients suffered from short-term local infections during different phases of treatment. Two patients suffered subluxation of a central incisor that healed uneventfully. Local discomfort due to delayed union (in three patients) and trauma to the lower lip (one patient) were also observed. CONCLUSION: The main problems were high local infection rates and damage to an apex that required a root filling, as well as patient discomfort due to delayed union and/or the bulkiness of the TMD device. Based on the results of this morbidity study, modifications are recommended for both the surgical protocol and the TMD device hardware.

Anterior transmandibular osteodistraction: clinical and model observations.

INTRODUCTION: The aim of this paper was to study the effect of transmandibular distraction on the periodontal and dental structures, and the initial movements of the mandibular halves, when using an axial plane non-rigid bone-borne distractor (TMD). MATERIAL AND METHODS: Fourteen patients undergoing bimaxillary transverse osteodistraction had their six lower anterior teeth assessed for mobility, sensitivity, and pocket depth. Recordings were made pre-operatively, post-distraction, post-consolidation and at 1-year follow-up. Selected landmarks on pre-operative and post-consolidation models were also digitised in three dimensions to study individual tooth movements, and positional changes of the mandibular halves. RESULTS: Pockets depths around the incisor teeth increased during the consolidation period (probably due to reduced oral hygiene), but returned to normal by the 1-year post-operative consultation. Tooth mobility increased temporarily in the active phase (central incisors, lateral incisors) and in the consolidation phase (lateral incisors, canine teeth). Sensitivity to cold was temporarily lost in the incisor teeth, probably as a result of 'apical contusion'. One central incisor was inadvertently apically osteotomized and needed root canal treatment. The angle between the mandibular halves closed by 9.4 degrees. CONCLUSION: Periodontal and dental morbidity is transient and limited to the distraction and consolidation period, as long as the tooth apices are avoided when the osteotomy is performed. A step-design osteotomy may be preferable when the central incisor apices are close to each other. The transmandibular distractor (TMD) allows for rotation at the temporomandibular joints.