Surgical principles and oral surgery

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   Mandible > maxilla.

   Stage 1: asymptomatic bone exposure/necrosis.

   Stage 2: symptomatic bone exposure/necrosis.

   Stage 3: as for stage 2, but includes extra-oral sinus/pathological fracture/osteolysis to lower border.

Prevention

   Ensuring dental health before starting therapy—referral from GMP or oncologist to GDP.

   Avoidance of extractions once on bisphosphonates.

   Regular dental care.

   No evidence that stopping bisphosphonates decreases risk or aids management of BRONJ.

   If extractions are required ADA and BDA do not recommend cover with peri-operative prophylactic antibiotics, although it is commonly employed.

Management of BRONJ

   Should be conservative—further intervention risks further necrosis.

   Any debridement should be minimal.

   Biopsy may be necessary to rule out malignancy—submit tissue for microbiology also.

   Antibiotics if symptomatic, guided by C&S.

   Progression of necrosis is frequent and may result in pathological fracture—mandibular resection ± reconstruction may be indicated.

Osteoradionecrosis

Definition

Osteoradionecrosis (ORN) is a condition of non-vital bone in a site of radiation injury characterized by:

   Hypovascularity.

   Hypocellularity.

   Hypoxia.

    ± Injury leads to three grades of disease:

   Grade I: most common, exposed alveolar bone.

   Grade II: ORN that does not respond to hyperbaric oxygen (HBO) therapy and requires sequestrectomy/saucerization.

   Grade III: demonstrated by full-thickness involvement and/or pathological fracture.

Cause

   Rare in patients who receive <60Gy radiation therapy.

   Incidence decreased over the last 3 decades.

   Incidence is increased in patients who receive combined chemo-radiation.

   Injury:

    •   none;

    •   tooth extraction;

    •   related cancer surgery;

    •   biopsy;

    •   denture irritation;

    •   exposure of the irradiated bone under soft tissue necrosis;

    •   implant placement (success in irradiated bone 60 vs 95% in non-irradiated).

Clinical symptoms/signs

   Pain.

   Swelling.

   Trismus.

   Exposed bone.

   Pathological fracture.

   Malocclusion.

   Oro-cutaneous fistula.

Prevention

   Dental assessment and extractions before cancer surgery, and at least 2 weeks before RT (head and neck cancer MDT should have restorative dentist as a core member).

   Maintenance of dental health post-treatment of patients who have had RT to the jaws.

   Extractions after RT—wait until mucositis has subsided.

   ORN risk is greater beyond 18 months after finishing RT.

   Mandible > maxilla.

   Suggested ways to reduce risk of ORN in extractions in irradiated bone:

    •   pre-operative HBO?

    •   avoid LA with adrenaline;

    •   atraumatic technique;

    •   antibiotic prophylaxis;

    •   pentoxifylline?

Management of ORN

   Oral hygiene/chlorhexidine.

   Antibiotics guided by C&S.

   Minimal intervention/sequestrectomy.

   Vascularized free tissue transfer in Stage III disease:

    •   composite flap to replace irradiated bone and mucosa;

    •   higher flap failure and complications than non-irradiated recipient site.

   HBO in ORN remains controversial. Marx reported high success with HBO in treating established ORN (Marx protocols), but these results have not been reproduced in subsequent studies.

   Small early studies of pentoxfylline and tocopherol (vitamin E) with clodronate show promise.

Dento-alveolar surgery

Third molars/impacted wisdom teeth

   Commonest missing tooth—25% of all third molars missing.

   Eruption average age 16–25 years.

   May remain unerupted.

   Commonly become impacted.

   Impaction—soft tissue only or bony.

   Bony impaction:

    •   vertical 38%;

    •   mesio-angular 44%;

    •   disto-angular 6%;

    •   horizontal 3%.

   Still in top 15 NHS UK surgical procedures.

    Removal of symptomatic wisdom teeth (see NICE guidance, image NICE guidelines regarding wisdom teeth (2000), p. 390) is justified, with benefits outweighing risks of removal. No RCTs compare the long-term outcome of early removal with retention of pathology free third molars.

Possible consequences of retention

   Removal when older with ↑ surgical and general complications.

   Dentigerous cyst formation (rare).

   Caries in distal aspect of second molar.

   No evidence of association with lower incisor crowding.

Possible consequences of removal

   Nerve damage lingual/ID.

   Dry socket (3–35%).

   Infection.

   Bleeding.

   Swelling.

   Trismus.

   Rarely iatrogenic # of mandible.

   Oro-antral fistula.

   Displacement of upper third molar into maxillary sinus or infra-temporal fossa.

   Displacement of lower third molar into sub-lingual or sub-mandibular space.

   Damage to second molar restoration.

   TMJDS.

Controversies in wisdom tooth removal techniques

   Flap design: triangular, envelope.

   Lingual flap retraction ± nerve protection.

   Bone removal:

    •   site: buccal approach vs lingual split;

    •   method: drill vs chisels.

   Tooth division: drill vs osteotome.

   LA vs GA: bilateral lower wisdom tooth removal under LA has been shown to be a safe technique.

BMJ Clinical Evidence (web publication May 2008) has looked at the evidence for different surgical methods of removing wisdom teeth. Despite much well-known work in the field of lingual nerve injury following wisdom tooth removal, there is no good quality evidence to support the practice or not of retraction. Some studies have shown a higher incidence of lingual nerve damage (up to 9.1%) when a retractor is used, but there is some suggestion that this is operator dependant. In skilled hands, careful lingual nerve protection when the retractor has been correctly inserted puts the nerve at less risk from bur/chisel trauma.

Lingual nerve damage

   Incidence varies widely between studies: 0–22%.

   Permanent disturbance 0–2%.

   Causes:

    •   damage by retractor;

    •   damage by bur/chisel.

ID nerve damage

   Temporary up to 5% (more related to anatomy). One RCT demonstrated up to 19% incidence in high-risk cases where coronectomy may have been indicated.

   Permanent 0.2–1%.

Nerve damage in wisdom tooth removal

Seddon’s classification of nerve injury:

   Neuropraxia: physiological disruption, but anatomy intact.

   Axonotmesis: axons disrupted, epi- and peri-neurium preserved.

   Neurotmesis: severed nerve.

In theory, neurotmesis has a greater chance of recovery if the severance has occurred in a bony canal, rather than in soft tissue (ID vs lingual).

    After peripheral nerve injury, proximal axons suffer retrograde degeneration, which may extend as far as the cell body (trigeminal ganglion for ID and lingual). The distal axonal segments undergo Wallerian degeneration with loss of the myelin sheath. Axonal regrowth occurs at up to 2mm/day.

Definitions of altered sensation

   Hypoaesthesia: ↓ sensation.

   Paraesthesia: altered sensation.

   Dysaesthesia: unpleasant sensation.

   Anaesthesia: no sensation.

Factors predictive of difficulty in wisdom teeth removal

Winter’s lines are described historically, but are rarely used in practice.

   Type of impaction.

   Depth of application point.

   Density of bone (age, ethnicity).

   Surgical access (trismus, obesity).

   Root morphology.

   Proximity to inferior dental bundle (IDB).

   Associated pathology.

Radiographic signs of close involvement with inferior dental bundle

   Narrowing of canal.

   Loss of lamina dura.

   Change in direction of canal.

    If involvement is suspected:

Cone beam CT scan

   Consider tooth division.

   Consider coronectomy (one RCT has shown 0% ID damage vs 19% where root removal completed in high-risk cases). However, coronectomy failed in 38%, i.e. roots were dislodged. Follow-up was 2 years and thus fate of retained roots undetermined.

IDN injury

   If noted at time of surgery immediate repair should be undertaken, but technically challenging.

   If noted at review monitor with light touch perception/sharp and blunt discrimination ± two point discrimination. If no improvement, consider referral to specialist unit.

Management of lingual nerve injuries following wisdom tooth removal

   Recovery not guided by bony canal.

   Heterogeny of fibre types vs IDB makes regeneration back to correct receptors less likely.

   Exploration and repair indicated at 3 months if no recovery.

   Success variable: consider referral to specialist unit.

NICE guidelines regarding wisdom teeth (2000)

Prophylactic removal of wisdom tooth is no longer indicated. Removal of wisdom teeth should be limited to patients with evidence of pathology:

   Severe or recurrent pericoronitis.

   Unrestorable caries/distal caries in adjacent molar.

   Non-treatable pulpal and/or peri-apical pathology.

   Cellulitis.

   Abscess and osteomyelitis.

   Internal/external resorption of tooth/adjacent teeth.

   Fracture of tooth.

   Disease of follicle including cyst/tumour.

   Tooth/teeth impeding surgery or reconstructive jaw surgery.

   Tooth involved in/within field of tumour resection.

    In Scotland the SIGN guidelines apply.

Apicectomy and RRF

Indications

   Failure of orthograde approach where repeat endodontic therapy may be detrimental to tooth or cannot be repeated.

   Post crown on tooth with apical pathology and a good coronal seal, where crown and post removal risks root fracture.

   Inaccessible apical one-third of root, e.g. calcification, curved, or open apex.

   Root perforation (often poor prognosis).

   Fractured and symptomatic apical one-third following trauma.

   Apical pathology requiring biopsy or enucleation of cyst.

Contraindications

   Unrestorable tooth.

   Periodontal disease/perio-endo lesion.

   Furcation involvement.

   Proximity to IDB.

Flap designs

   Edges should be on sound bone.

   Two- or three-sided gingival margin:

    •   good access;

    •   ↑ recession around crown margins;

    •   indicated in ?buccal post perforation;

    •   more difficult to suture.

   Luebke–Oschenbein flap is three-sided, but supragingival. Unwise in possible post perforation, but good access and easy to suture.

   Semilunar flap gives reduced access, less easy to suture than Luebke–Oschenbein, wound can dehisce.

Points

   Apical soft tissue should be sent for histology.

   Apical radiolucency over 1cm likely to be radicular cyst, rather than apical granuloma (a collection of granulation tissue, not containing histological granulomata).

   Apex removal resects the apical delta of canals and enables retrograde root-filling to be placed.

   Apicectomy should be close to 90° to reduce surface area of exposure of transected dentinal tubules.

   At least 3mm should be apicected.

   Retrograde cavity preparation with ultrasonic tip is recommended by endodontists.

   Retrograde materials:

    •   mineral trioxide aggregate (MTA)/Portland cement;

    •   super EBA;

    •   glass ionomer;

    •   composites for dentine;

    •   intermediate restorative material (IRM)—ZnO/Eugenol based;

    •   amalgam success rate low and introduces mercury into the tissues—possible toxicity therefore no longer recommended.

   Success rates vary in literature from 30–90% higher on upper anteriors and single-rooted teeth.

   Success rates for repeat repair or pre-existing loss of supporting bone low (<40%).

Dento-alveolar surgery for orthodontics

   Upper labial fraenectomy.

   Impacted canines.

   Exposure of impacted/unerupted teeth.

   Miniscrews for anchorage.

Upper labial fraenectomy

   No adequate RCTs exist comparing no intervention with surgery.

   An upper midline diastema is common in the mixed dentition and often closes with eruption of the permanent canines.

   Fewer carried out than in the past.

   Fraenectomy theoretically only of value in helping to close a midline diastema if traction on it produces movement of the incisive papilla.

   Excision of the fraenum must include that part which passes between the upper incisors.

   Some advocate a bur cut—no studies support this and there is a risk of damage to the roots of the upper central incisors.

Management options for impacted canines

   Keep deciduous canine and leave permanent in situ.

   Keep deciduous canine and remove permanent.

   Remove deciduous and permanent canines, and close space/place implant.

   Expose and bond permanent canine. Consider retaining deciduous temporarily if permanent well displaced. May also require removal of adjacent first premolar.

   Transplantation—poor success rate.

   Decision regarding best option result of discussions including patient (± parents) and orthodontist.

Exposure of impacted/unerupted teeth

   Aim to remove bone/mucosa preventing eruption, and enable orthodontic bonding and traction to align the tooth.

   Commonly upper canine teeth, occasionally upper incisors (often following previous supernumery removal or trauma), lower premolars.

   Association between ectopic teeth and missing teeth.

   If canines are not buccally palpable at age 10 consider palatal position.

   Extraction of deciduous canines at age of 10 years will allow spontaneous alignment of 75% of ectopic permanent canines.

Procedure

   Palatal canines:

    •   exposed through a palatal flap (usually under GA);

    •   bone removal to expose tip and maximum convexity of crown;

    •   options: bonding a bracket and chain ± re-covering: excision of overlying palatal mucosa + WHP dressing or cover plate;

    •   Cochrane review 2008: no evidence to support one surgical technique over another.

   Buccal teeth: exposure with an apically repositioned flap ± bonding of bracket at surgery or later.

Miniscrews/plates

   Provide bony anchorage.

   Increasingly popular.

   NICE guidance advises use should be audited.

Odontogenic infections

   Infections associated with teeth.

   Definitive treatment is drainage of the infection/pus and/or removal of the offending tooth/pulp.

   Infections are bacterial—arising from necrotic pulp, pericorontitis, and periodontal pockets.

Severe infections

   Can be life-threatening emergencies as they spread into the potential fascial spaces within the head and neck.

   Can track into the cavernous sinus or mediastinum.

   Pus in the potential spaces in the head and neck is a serious hazard to the airway and requires urgent management.

   Severity depends upon:

    •   local anatomy;

    •   virulence of the organisms;

    •   host resistance.

Microbiology

   Mixed infection: Bacteroides (anaerobic) and Streptococcus (aerobic and anaerobic).

   Usually sensitive to penicillins.

   Resistance rare.

Fascial tissue spaces

These are potential spaces between tissue planes which can fill up with pus—the opening of planes aided by enzymatic tissue lysis caused by pathogenic bacteria.

   Buccal space:

    •   commonest space to be affected by a dental abscess, both from upper and lower teeth;

    •   bounded by buccinator attachment;

    •   contains the buccal fat pad;

    •   can usually be drained intra-orally.

   Masticator space:

    •   involved in molar teeth abscesses, lower more than upper;

    •   bounded by muscles of mastication.

   Deep masticator space:

    •   lies between the pterygoid muscles and mandibular ramus;

    •   superficial masticator space lies laterally to the ramus and comprises the submasseteric space below the superficial temporal space;

    •   infection gaining access to the pterygoid space can potentially spread intra-cranially;

    •   deep masticator space gives access to the parapharyngeal space that, in turn, contains the carotid sheath giving potential access for pus to track to the mediastinum.

   Parotid space lies within the parotid fascia.

   Sublingual space:

    •   lies between the floor of the mouth and mylohyoid muscle;

    •   communicates around its free posterior edge with the submandibular space in the neck.

   Ludwig’s angina is defined as bilateral cellulitis of the submandibular and sublingual spaces.

   Canine fossa:

    •   bound by the peri-oral muscles of facial expression;

    •   infection can spread via the ophthalmic veins to the intracranial circulation.

Diagnosis

   Severe pain.

   Swelling.

   Discharge.

   Swinging pyrexia.

   Tachycardia.

   Raised white cell count.

   Later:

    •   drooling;

    •   difficulty breathing or speaking;

    •   severe trismus;

    •   stridor (inspiratory wheeze).

   Death by septicaemia/respiratory arrest/intra-cranial or intra-thoracic complications.

Treatment

   Involve senior anaesthetic help early.

   Fibre-optic intubation and/or a surgical airway may be indicated.

   Urgent incision, drainage, and exploration of fascial spaces, multiple drain insertion + extraction of offending tooth.

   High-dose antibiotics (triple therapy—amoxicillin/gentamicin/metronidazole) ± steroids.

   Mortality of Ludwig’s angina is 5%.

Necrotizing fasciitis

   Rare.

   High mortality.

   Polymicrobial Streptococcus/Staphylococcus/Bacteroides/Clostridia.

   Monomicrobial: group A streps or MRSA.

   Usually in occurs in the immunocompromised.

   Treatment is wide surgical debridement and IV antibiotics.

Osteomyelitis

   Rare—acute or chronic.

   Secondary to immunosuppression/diabetes in developed world.

   Common in developing world secondary to odontogenic infection/fracture.

Microbiology

   Bacteroides spp.

   Staph. aureus.

   Klebsiella.

   Proteus.

Signs/symptoms

   Pain.

   Trismus.

   Tooth mobility.

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Mar 2, 2015 | Posted by in Oral and Maxillofacial Surgery | Comments Off on Surgical principles and oral surgery
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