Management of OsteoRadioNecrosis – a Literature ReviewBy Dr Ashok Ramadorai28 May 2002

A. Definition

ORN is essentially a chronic non-healing wound with nonviable dead bone.

Marx and Johnson 1987 1

An exposure of nonviable irradiated bone which fails to heal without intervention.

Harris 1992 2

Exposed irradiated bone that fails to heal over a period of 3 months in the absence of local tumor.

Beumer et al. 1983 3

Exposure of bone of the maxilla or mandible within the radiation treatment volume persisting for more than 3 months or longer.

B. Pathophysiological Sequence

Radiation development of hypovascular-hypocellular-hypoxic tissue due to trauma or spontaneous tissue breakdown a non-healing wound.

Aetiopathogenesis:

ORN is an imbalance in bone homeostasis ie. the cells are lethally affected by the ionizing radiation resulting in slow bone turnover.

The cells can perform only their vegetative function and cannot divide. The wound does not heal as the metabolic demands exceed O2 and vascular supply. It is not an infectious process and microorganisms play only a contaminant role. It becomes septic ORN if there is a secondary infection of dental, periodontal or

traumatic origin.

C. Incidence 4

Horiot 1981 2%

Beumer 1983 11%

Morton 1986 20%

Marx 1987 5.4%

Before 1968(prior to mega voltage DXT) Lewis Clayman 1997 11.8%

After 1968 (after of mega voltag DXT) Lewis Clayman 1997 5.4%

D. Clinical Features

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1. Intractable pain2. Non-healing extraction socket3. Exposed nonviable non-healing bone4. Evidence of osteolysis of the inferior border of the mandible 5. Pathological fracture or orocutaneous fistula or both

E. Diagnosis

1. Diagnosis of exclusion, no evidence of persistent or recurrent cancer that could account for Exposure.

2. Tissue biopsy from the wound can be helpful to demonstrate hyperemia, inflammation (endarteritis), thrombosis, cellular loss, hypovascularity and fibrosis.

3. Culture from wound to assess presence of secondary infection (septic ORN).4. Differential diagnosis - chronic osteomyelitis.

F. Predisposing factors

1. Post-irradiation extraction2. Periodontal disease3. Trauma4. Irritation from prosthesis5. Jaw operations due to residual or recurrence of tumour

G. Risk factors

1. Patients who receive a total of 80Gy have 2.9 fold higher risk.2. Dentate patients have 2.6 fold higher risk.

H. Treatment Regimes of Osteoradionecrosis

1. Prevention2. Conservative management3. Ultrasound therapy and metronidazole 4. Surgery and adjunctive HBO5. Radical resection and reconstruction using vascularised bone grafts

1. Prevention 1

Introduction of meticulous dental evaluations before and after irradiation, caries and plaque control, patient education.

Teeth to be removed prior to radiation should be removed 21days prior to DXT (Marx and Johnson 1987).

*NDC practice: Extractions are completed 7–10 days prior radiotherapy so as not to delay the start of the radiotherapy.

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Dental Extraction Protocol (1982 study in Princess Margaret Hospital, Canada) 5

Prophylactic oral Penicillin –2G one hour prior to procedure. Low concentration epinephrine (containing less than 1: 200,000 epinehrine) local

anaesthetic or prilocaine. A traumatic surgical technique avoiding periosteal elevation, surgical site

approximation using sutures. In case of multiple extractions one or two teeth to be extracted at one appointment. Post-extraction Penicillin V 600mg qid for 10 days.

Results:Incidence of ORN - 0% (including those extracted directly in and those outside the irradiated area).

*NDC practice: No prophylactic antibiotics is given and post-extraction Amoxycillin 500mg tds and Metronidazole 200mg

2. Conservative Management 6

Local irrigation of saline or 0.2% chlorhexidine mouthwash. Systemic antibiotics in acute infectious episodes. Oral hygiene instructions. Avoidance of local irritants eg, tobacco, alcohol, denture use.Gentle removal of sequestrating lesions with or without local anesthesia, in addition to the above methods.

Results: Resolution - from the date of bony exposure first noted to the date at which mucosal

cover was established (48.3% of patients).

Improvement - decrease in the size of exposure and symptoms (3.4% of patients).

Stable - a symptomatic but exhibiting persistent bony exposure up until death or commencement of the study (13.8%).

3. Local Debridement, Ultrasound Therapy and Oral Metronidazole 2

Local debridementWhen healing proved to be slow with persistent bony exposure, the area is treated surgically with debridement of the exposed bone with saline cooled acrylic bur followed by local flap of non-irradiated tissue (adjacent mucosa for primary closure or lateral tongue flap, temporalis flap).

Ultrasound programme of 1 watt/sq.cm 3 mega Hz, pulsed 1:4 15 mts per day for 60 days

Metronidazole 400mg tds Cephalexin 500mg tds for patients intolerant to metronidazone. Antibiotics are continued until the area is free of inflammation and discharge.

Results:The above regime achieved healing in 48% of patients.

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*NDC Practice: No experience with adjunctive ultrasound therapy. 4. ORN Treated by Surgery and Adjunctive HBO 1

Protocol for prophylactic HBO

20/10 (20 prior to surgery and 10 post operative) 100% O2 at 2.4 ATA 90 minutes per dive 5 day week (no interruptions of more than 3 days)

Protocol of HBO in the treatment of established ORN (Marx -University of Miami )

30/10 (30 prior to surgery and 10 post operative) 100% O2 at 2.4 ATA 90 minutes per dive 5 day week (no interruptions of more than 3 days)

*NDC practice: Not in current practice due to limited access to the HBO facility at Naval Medicine & Hyperbaric Centre previously. HBO is now available at the Hyperbaric Medicine Centre, Tan Tock Seng Hospital. Each dive session costs $260, of which $100 is Medisave- deductible. An average course of 30 dives would cost approximately $7,800.

5. Radical Resection with Reconstruction Using Vascularised Bone Grafts 7

For patients with persistent fistulation after repeated debridement, partial mandibulectomy and its reconstruction using microvascular transplantation is indicated eg fibula osteoseptocutaneous flap.

Results:

No flap failure was noted. 100% of cases primary bone healing was obtained. 90%of cases there was relief of preoperative severe pain. 71% of cases trismus improved. 83 % of cases swallowing restoration was obtained in two to four weeks.

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Use of HBO in ORN (Marx University of Miami Protocol) 1

Stage 1 30 x 100% O2, for 90 mts at 2.4

ATA examine exposed bone

No surgeryNo antibiotics

Saline rinsing only

No response

Cutaneous fistula Pathological

fracture Resorption of

inferior border of mandible

Response

10 x (100% O2 for 90 minutes at 2.4 ATA) (Stage I responder)

Stage II Surgery (maintain inferior border of

mandible) 10 x (100% O2 for 90 minutes at 2.4 ATA)

Response No response

Healing without exposed bone (Stage II responder)

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Stage III Excision of non-viable bone Fixation of mandibular segments 10 x (100% O2 for 90 minutes at 2.4

ATA) Reconstruction after 3 months No further HBO required

Analysis of 300 cases of ORN in USNon HBO 62 pts 8% resolutionHBO without surgery 51 pts 17Marx UM Protocol 130 pts 100Marx UM in private practice 54 pts 100

References

1 Marx and Johnson. Studies in the Radiobiology of Osteoradionecrosis and their Clinical Significance. Oral Surg Oral Med Oral Path 1987; (64)4:379-390

2 Malcolm Harris. The Conservative Management of Osteoradionecrosis of the Mandible with Ultrasound Therapy. BJOMS 1992; 30:313-318

3 Beumer III J, Harrison R, Sanders B, Kurrasch M. Postradiation Dental Extractions: a Review of the Literature and a Report of 72 episodes. Head Neck Surg 1983;6:581-6

4 Lewis Clayman. Management of Dental Extractions in Irradiated Jaws: A Protocol without Hyperbaric Oxygen Therapy J Oral and Maxillofac Surg 1997; 55,275-281

5 W.G.Maxymiw and R.E. Wood. Postradiation Dental Extractions Without Hyperbaric Oxygen. Oral Surg Oral Med Oral Path 1991; 72:270-274

6 J.K.Wong and R.E.Wood. Conservative Management of Osteoradionecrosis. Oral Surg Oral Med Oral Path Oral Radiol Endod 1997; 84:16-21

7 Santamaria,Eric M.D. Fibula Osteoseptocutaneous Flap forReconstruction of Osteoradionecrosis of the Mandible. Plast Reconstr Surg 1998; 101(4): 921-929

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