Validation of athe conchotome percutaneous technique to perform a muscle biopsy to measure biochemical parameters in mitochondrial disease

Mitochondrial diseases are disorders in which energy metabolism is disturbed.
Patients with these conditions may present with a variety of symptoms from
different organs. This makes it difficult to make a diagnosis on clinical
grounds.

The diagnosis of mitochondrial disease is based on the analysis of energy
production (ATP), processing sugar (substrate oxidation rates) and the activity
of different enzyme complexes of the respiratory chain in muscle cells. These
muscle cells are obtained by a piece of muscle removed by an open muscle biopsy
of the musculus vastus lateralis. This requires children a day are included and
are placed under general anesthesia. With this study we want to see if it is
possible with a less invasive technique to obtain muscle cells in which the
various biochemical processes can be studied.

In Sweden and England, standard biopsies are obtained from the tibialis
anterior muscle under local anesthesia.
This less invasive technique would have several advantages over the open muscle
biopsy. Children no longer need to be anesthetized. It is known that children
with mitochondrial disease have an increased sensitivity to anesthesia.
Moreover, it is really undesirable for children with muscle weakness to
anesthetize. The conchotome percutaneous muscle biopsy is performed under local
anesthesia in combination with Midazolam. Besides the replacement of general
anesthesia by giving Midazolam, the diagnostic process will be accelerated
introducing this method.

Should this study show that a conchotome percutaneous muscle biopsy is only
valid for measuring energy production and not for substrate oxidation rates and
enzyme complex activities, it is also possible to provide accessible screening
for mitochondrial dysfunction in a larger group of patients. A open muscle
biopsy will only be performed in those children who have a high suspicion,
based on clinical symptoms or a combination of clinical symptoms with a
decreased energy production in the conchotome percutaneous muscle biopsy.
Hereby, fewer patients will be anesthetized unnecessarily.
Although there is currently no treatment for mitochondrial diseases, to find a
diagnosis is of major importance for the child and the family. The clinical
condition of the child can be managed by the improvement of nutrition, exercise
and avoiding certain medications. For the family it is generally important to
have a diagnosis because of psychological aspects and related to family
planning. Moreover, in mitochondrial mutations that have an inheritance of
theoretically 100%, other affected family members detected early and treated
preventively. Also, the conchotome percutaneous muscle biopsy may be a good
follow-up tool for future experimental treatments.

Primary objective:
The validation of the conchotome percutaneous muscle biopsy to measure ATP
production in patients suspected of mitochondrial disease.
Secondary objectives:
The validation of the conchotome percutaneous muscle biopsy to measure
substrate oxidation rates and enzyme complex activity in patients suspected of
a mitochondrial disorder.
Register the complications of conchotome percutaneous muscle biopsy.

This study will be conducted in phases. In the first phase, the diagnostic
value of the method investigated (the correlation between the gold standard and
the values found in the biopsy is done with the new method) in 10 patients.
Thereafter, 30 additional patients will be added to this study to obtain
reference values, in which the musculus vastus lateralis value (gold standard)
is used as a reference for the new biopsy.

Patients suspected of a mitochondrial disease, planned for an open muscle
biopsy will be contacted for participating in this study.
After informed consent a piece of tissue be removed through the conchotome
percutaneous muscle biopsy will be removed, in combination with the open muscle
biopsy under general anesthesia.

The procedure of conchotome percutaneous muscle biopsy, as implemented in
Sweden and England, is as follows:
- Midazolam Sedation by 0.3 mg / kg oral / rectal
- Pain relief by Paracetamol 20 mg / kg oral / rectal
- Local anesthesia using Lidocaine 2 cm around the site of incision
(To avoid injecting into the muscle)
- Incision (0,5 - 1 cm) of skin and fascia with a scalpel with a straight tip
- Collection of 40 mg of muscle with a nasal forceps (Karl Storz 456 001)
- Directly in sterile 0.9% NaCl on ice.
- Analysis within one hour of both samples.
- Wound pressure
- Close to Steris Breaks
- Delete Steris Breaks after 1 week
- No severe exercise for 24 hours and no bath for 1 week

In our study we will not give Midazolam since the children are already under
anesthesia. The pain relief with acetaminophen is part of the protocol for open
muscle biopsy. Local anesthesia will be applied as they can intervene with the
confidence of the biopsy.

The conchotome percutaneous muscle biopsy will take about 10 minutes extra,
since it probably not possible to perform it parallel with the open muscle
biopsy.

The complications of the incision will be prosecuted by the responsible nurse.

The principal investigator will learn the technique of conchotome percutaneous
muscle biopsies in Sweden. All conchotome percutaneous muscle biopsies will be
performed by the principal investigator.

In this study we will acquire a piece of muscle under general anesthesia.
Obviously this procedure has a risk on complications such as bleeding,
infection and pain. Also there will be an additional scar from approximately
0,5 - 1 cm. It is known that complications of a open muscle biopsy are very
rare, after the operation where a 4 cm incision is made. We therefore expect
few complaints of this additional incision.
We consider the risk very small compared to the benefits which can be booked
for the diagnostic procedure for mitochondrial diseases.