**Core Concept:** Muscular dystrophies are a group of genetic disorders characterized by progressive muscle weakness and wasting. Duchenne muscular dystrophy (DMD) is the most common and severe form of muscular dystrophy, affecting primarily boys. Tendon lengthening procedures are often needed due to the progressive contracture of muscles in these patients. Anaesthesia for these procedures requires careful consideration of the patient's condition, potential complications, and the need for long-acting muscle relaxants.

**Why the Correct Answer is Right:**

For tendon lengthening procedures in Duchenne muscular dystrophy patients, the most appropriate anaesthetic choice is D (General Anaesthesia with muscle relaxants). This is due to the following reasons:

1. **General Anaesthesia**: Provides effective immobilization of the patient's limbs, allowing precise control over muscle relaxation during the procedure.
2. **Muscle Relaxants**: These drugs are essential to prevent excessive muscle contractions that can lead to injury, complications, and prolong the procedure time.
3. **Protection from Muscle Damage**: Duchenne muscular dystrophy patients have a high risk of muscle damage due to the underlying muscle weakness. General anaesthesia with muscle relaxants helps to protect the muscles by minimizing unnecessary contractions during the procedure.

**Why Each Wrong Option is Incorrect:**

A: General anaesthesia without muscle relaxants would not be effective in providing immobilization during the procedure, leading to injury and increased procedure time.
B: Regional anaesthesia may not be sufficient to immobilize the affected limbs effectively, potentially causing injury during the procedure.
C: The use of local anaesthesia alone would not provide adequate muscle relaxation, increasing the risk of injury and prolonging the procedure.

**Clinical Pearls:**

1. **Muscle Relaxants**: Choose a balanced anaesthetic regimen that includes a combination of short-acting and long-acting muscle relaxants, such as succinylcholine for intubation and rocuronium for maintenance.
2. **Procedure Safety**: Ensure proper monitoring of vital signs and cardiac and respiratory functions to manage complications, such as hypotension, bradycardia, hypoxemia, and respiratory depression.
3. **Post-operative Care**: After the procedure, ensure close monitoring of the patient for respiratory and cardiac complications, as well as monitoring for muscle weakness recovery.