DISTRACTION OSTEOGENESIS VS BSSO
INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com www.indiandentalacademy.com
INTRODUCTION ď‚— BSSO and DO are the most common technique
currently applied to correct mandibular retrognathia ď‚— But it is the responsibility of the maxillofacial surgeon to determine the optimal treatment option in each individual case.
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AIM OF THE STUDY Was to review the literature on BSSO and DO for
correction of non-syndromic deficent mandible with emphasis on influence of Age Post surgical growth Damage to inf.alv.N Post surgical stability Relapse
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MATERIALS AND METHODS Literature from january1995 to august 2006 was searched on Mandibular advancement and mandibular surgery distraction osteogenesis Angle class II child,inferior alveolar nerve,mandibular condyle,retrognathism,stability,TMJ,patient satisfaction.
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ď‚— Unfortunately randomized clinical trials are lacking
and thus could not be used as an inclusion criterion for the literature search.
ď‚— The result were classified according to age and post
surgical growth,nerve damage,stability and relapse,and patient-centred out come.
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AGE: ď‚— DO is more advantageous than BSSO in actively
growing children ď‚— Facial growth completion of approximately 98% occurs in girls boys 15 yrs 17-18 yrs Above the age of 5 yrs,the basic dentoskeletal morphology is established(almost >97%) www.indiandentalacademy.com
Difficulties of performing BSSO in younger patients due to: 1)greater bone elasticity 2)thick cortical bone 3)unerupted molar 4)lingula-more posterior
and superior placement
As per studies BSSO may be used as safe technique in growing children with no restrictions on post surgical vertical mandibular growth,but should be applied with caution in youngsters. www.indiandentalacademy.com
Difficulties of performing DO ď‚— 1)patient and parent compliance ď‚— 2)high risk of damaging tooth bud
But DO is easily accomplished in growing children due to high bone regeneration potential.
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NERVE DAMAGE ď‚— Permanent neurosensory disturbance is a common
complication which may be correlated with age
magnitude of mandibular advancement Older patientmechanical tearing poor regeneration of axon ischemia by compression of vasa nervosum www.indiandentalacademy.com
The strech injury from DO beyond the adaptive
capacity of the nerve may result in serious damage(>7mm) Therefore distraction rate should not exceed 1mm/24hr which may result in either no change in sensation or there may be a short period of decreased function following gradual recovery. After large mandibular advancements in older patients the risk of permanent sensory nerve damage is high in BSSO than in DO www.indiandentalacademy.com
STABILITY AND RELAPSE ď‚— Different types of rigid fixation methods are used to
decrease soft tissue tension Causes of relapse: 1)Anatomic locationa)osteotomy site-slippage of fragment -perimandibular soft tissue tension. b)TMJ-due to condylar malpositioning or resorption www.indiandentalacademy.com
2)high mandibular plane angle 3)amount of advancement 4)non compliance of patient 5)persistant growth 6)progressive condylar resorption(more in BSSO,but in
DO the force of 1mm/day is gradual and resorption is less).
BSSO is considered a stable procedure with minimal relapse in patients with normal or decreased facial height,whereas it shows a tendency for relapse in high mandibular plane angle and when advancements>7mm was used. DO showed less relapse after advancement of 10mm or more www.indiandentalacademy.com
PATIENT CENTERED OUTCOME Discomfort experienced by patients are1)General anesthesia 2)Post operative diet and weight loss 3)Absence from work/school 4)Regular check ups 5)Numbness 6)Damage to dentition 7)Swelling,pain,hemorrhage 8)Post surgical infections www.indiandentalacademy.com
Discomforts in patients during DO: Routine activities are disturbed during DO. Duration of hospitalization is less in DO than in BSSO,but DO requires a 2nd surgical intervention for removal of the distraction device.
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DISCUSSION DO
BSSO
AGE
early intervention possible POST SURGICAL GROWTH growth seen NERVE INJURY with distraction rate of 0.51mm/day,no long term damage seen with large advancement.
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only after 12yrs
no much growth seen
High with age>30yrs &>7mm advancement
DO
BSSO
MANDIBULAR PLANE
ANGLE (MPA) Normal/low MPA-less relapse(due to osteotomy cut distal to pterygomasseteric sling & less periosteal stripping.) High MPA-more relapse AMOUNT OF ADVANCEMENT 10mm or more PCR Advancement with in the physiological limit-reversible Injury PATIENT FACTOR More discomfort www.indiandentalacademy.com
Normal/low MPA-less relapse
High MPA-more relapse
7mm in low to normal MPA High progressive condylar resorption Less discomfort.
CONCLUSION Considering the literature available,there is support for
the assumption that DO might have advantages over BSSO in mandibular retrognathism ,in low and normal mandibular plane angle where large advancemnts are needed, since BSSO is associated with nerve injury and relapse. There is need of more randomized clinical trials comparing DO with BSSO in all types of retrognathia inorder to select the type of sugery…..
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