1. Radiotherapy in ENT (20 Marks)

Definition

Types / Modalities of Radiotherapy

• Source is at a distance from the patient (linear accelerator, Cobalt-60)
• Most common modality used in head and neck cancer

• Radioactive source placed directly into or close to the tumour (interstitial implants, moulds)
• Used for small, well-localized lesions e.g. early oral tongue, lip cancers

• 3D-Conformal RT (3D-CRT) - shapes the beam to the tumour volume
• Intensity Modulated Radiation Therapy (IMRT) - varies beam intensity across the field, allowing sparing of parotid glands, mandible, inner/middle ear, temporomandibular joints, optic pathways and brainstem while boosting the tumour dose
• Volumetric Modulated Arc Therapy (VMAT) - delivers IMRT-quality dose distribution in arcs, faster delivery with fewer side effects
• Image-Guided RT (IGRT) - uses imaging during treatment for precise targeting
• Stereotactic Radiosurgery/Radiotherapy (SRS/SRT) - for skull base tumours, glomus tumours, acoustic neuromas
• Proton beam therapy - emerging role, theoretical advantage of sharper dose fall-off (not yet proven superior in HNC)

Mechanism of Action

Fractionation

• Conventional fractionation: ~2 Gy/day, 5 days/week, total 60-70 Gy over 6-7 weeks
• Hyperfractionation: smaller doses more than once daily - reduces late toxicity
• Accelerated fractionation: same total dose in a shorter overall time - reduces tumour repopulation
• Duration of treatment is an important prognostic variable - prolonged overall treatment time worsens local control (shown for early glottic cancer)

Indications in ENT

• Early glottic and supraglottic laryngeal carcinoma (T1-T2) - excellent voice preservation
• Early nasopharyngeal carcinoma (radiosensitive, surgically inaccessible site)
• Early oropharyngeal carcinoma (tonsil, base of tongue), especially HPV-related
• Localized lymphoma of Waldeyer's ring
• Inoperable tumours or patients medically unfit for surgery

• After surgery for advanced (T3/T4) tumours
• Positive/close surgical margins
• Extracapsular nodal extension, perineural or lymphovascular invasion
• Multiple positive nodes
• Concurrent chemoradiation added when margins are positive or there is extracapsular spread

• Occasionally to downstage large tumours before resection

• Advanced/metastatic disease - relief of pain, bleeding, dysphagia, airway obstruction, and control of fungating neck nodes

• Nasopharynx - primary treatment of choice
• Larynx (early glottic) - primary treatment
• Oral cavity - mainly adjuvant after surgery
• Paranasal sinus and skull base tumours
• Salivary gland malignancies (adjuvant, or primary for adenoid cystic carcinoma with perineural spread)
• Thyroid cancer - radioactive iodine (differentiated), EBRT for anaplastic/medullary or unresectable disease
• Skin cancers of head and neck (BCC/SCC) in elderly or poor surgical candidates
• Glomus tumours, juvenile nasopharyngeal angiofibroma (unresectable/recurrent)

Complications of Radiotherapy

• Mucositis, odynophagia, dysphagia
• Hoarseness, dysgeusia (loss of taste)
• Skin erythema/dermatitis
• Acute xerostomia
• Weight loss

• Xerostomia (permanent salivary gland damage)
• Osteoradionecrosis of the mandible
• Fibrosis and trismus (temporomandibular joint/muscle fibrosis)
• Hypothyroidism (if thyroid is in field)
• Carotid artery rupture/stenosis
• Radiation-induced myelitis
• Radiation-induced secondary malignancy
• Sensorineural hearing loss, chronic otitis media (if ear structures irradiated)

Advantages of RT over Surgery

• Organ preservation (voice, swallowing function)
• No anaesthesia risk, suitable for unfit/elderly patients
• Treats microscopic disease and draining lymphatics simultaneously
• Better cosmetic outcome in many cases

Disadvantages

• Prolonged treatment course (6-7 weeks)
• Significant acute and late toxicity
• Radioresistant tumours (e.g., some sarcomas) respond poorly
• Difficult to treat recurrence in previously irradiated field
• Salvage surgery after RT failure carries higher complication rates

2. Temporomandibular Joint (TMJ) Arthroscopy and Its Indications (20 Marks)

Relevance to ENT

Relevant Anatomy (brief)

• TMJ is a synovial joint between the mandibular condyle and the mandibular (glenoid) fossa
• Divided into upper (gliding) and lower (hinge) compartments by an intra-articular fibrocartilaginous disc
• Articular surfaces are fibrous tissue, not hyaline cartilage
• Capsule attached to the fossa above and condylar neck below; lateral pterygoid muscle attaches to the disc/condyle anteriorly

Common TMJ Disorders Leading to Arthroscopy

• Internal derangement - anterior disc displacement with or without reduction (clicking, closed lock)
• Degenerative joint disease / osteoarthritis
• Chronic synovitis/capsulitis
• Adhesions and fibrosis
• Failed conservative therapy for TMD

Ladder of Treatment (Conservative to Invasive)

1. Patient education, soft diet, NSAIDs, splint therapy, physiotherapy
2. Arthrocentesis (joint washout under pressure) - for anchored disc phenomenon/closed lock unresponsive to 6 weeks conservative treatment
3. Arthroscopy - next step if arthrocentesis/conservative measures fail
4. Arthrotomy (open joint surgery) - débridement, disc repositioning/plication, discectomy, arthroplasty, total joint replacement - reserved for failed arthroscopy or severe structural disease

What is TMJ Arthroscopy

Indications for TMJ Arthroscopy

1. Painful internal derangement (anterior disc displacement with or without reduction) that has failed adequate conservative therapy (splints, NSAIDs, physiotherapy) and/or arthrocentesis
2. Chronic closed lock (disc displacement without reduction) not resolved by manual manipulation/arthrocentesis
3. Degenerative joint disease/osteoarthritis of the TMJ causing persistent pain and restricted movement despite conservative management
4. Adhesions and fibrosis within the superior joint space limiting movement
5. Chronic synovitis - for diagnostic visualization and biopsy of joint synovium
6. Painful but radiologically/clinically "normal" joints not responding to conservative treatment (diagnostic and therapeutic lavage)
7. To assess joint pathology prior to deciding on open surgery, and as a staged step before arthrotomy
8. Persistent trismus of joint origin unresponsive to conservative measures

Contraindications

• Local infection over the pre-auricular region
• Severe joint ankylosis (bony fusion - requires open surgery)
• Malignancy within or adjacent to the joint
• Anatomical distortion precluding safe portal placement (relative)

Procedure (brief technique)

• General anaesthesia
• TMJ region marked (canthal-tragal line landmarks) and infiltrated
• Arthroscope introduced into the superior joint space through an inflow portal
• Second (outflow/instrument) portal placed anteriorly
• Joint distended and irrigated with Ringer's lactate/saline; adhesions lysed, debris lavaged out
• Postoperative care: soft/non-chew diet for a few days, jaw range-of-motion exercises, analgesics

Outcomes / Success Rates

• Arthroscopic lysis and lavage reports 80-90% success in relieving pain and improving mandibular movement
• Long-term (5- and 10-year) follow-up studies (Murakami et al.) show outcomes comparable to open joint surgery for most stages of internal derangement
• Because results parallel arthrocentesis (a simpler procedure), many surgeons attempt arthrocentesis first, reserving arthroscopy for failures

Complications

• Injury to branches of the facial nerve (temporal branch), auriculotemporal nerve - usually transient
• Haemorrhage/haematoma
• Otologic injury (external auditory canal perforation) given proximity to the ear
• Joint effusion, transient malocclusion/posterior open bite
• Infection (rare)
• Instrument breakage within the joint (rare)

Advantages of Arthroscopy over Open Surgery (Arthrotomy)

• Minimally invasive, smaller incisions/portals
• Lower morbidity, less facial nerve risk
• Faster recovery, shorter hospital stay
• Allows direct visualization for accurate diagnosis while treating simultaneously
• Comparable long-term success to open surgery in internal derangement