Multiple Sclerosis (MS)


Multiple sclerosis (MS) is an autoimmune neurological disorder affecting the central nervous system that is characterized by progressive damage to myelin, a fatty coating surrounding the nerves. Myelin protects the nerves from damage and allows for faster communication between the brain and the rest of the body.1 

Disruption of signal conduction between the brain and the body results in symptoms such as tingling, numbness, tremors, fatigue, pain, spasticity, blindness, cognitive dysfunction, and muscle paralysis that affects voluntary movements, speaking, and swallowing.1,2 

Physicians often recommend surgical interventions to treat symptoms of MS, including implantation of an intrathecal baclofen pump or a deep brain stimulator, rhizotomy, or gastrostomy.2 

Intrathecal Baclofen Pump

Severe disruption of nerve signaling increases spasticity within muscle tissues, a frequent indicator of upper motor neuron syndromes like MS. Around 90% of patients with MS have spasticity. Spasticity is a velocity-dependent increase in muscle tone caused by hyperexcitable stretch reflexes. Because it causes increased muscle stiffness and involuntary contractions, spasticity makes voluntary movement difficult in patients with advanced MS.2-4 

Baclofen is a muscle relaxant that treats spasticity. When oral baclofen treatments fail in patients with MS, a physician may recommend surgical implantation of an intrathecal baclofen pump. The US Food and Drug Administration (FDA) first approved intrathecal baclofen treatment for severe spasticity as an orphan drug in 1992.5,6 

This pump is implanted under the skin. A long, thin tube delivers the medication from the pump directly to the cerebrospinal fluid surrounding the spinal cord. This method of baclofen administration may prove more effective for patients with MS because a consistent dose is delivered close to the site of injury (the spinal cord) with fewer side effects, which are more common with oral medications.2,4 

Candidates for intrathecal baclofen pump implantation may undergo a trial to evaluate their response to a spinal tap in which a small amount of baclofen is injected into the spinal fluid. If the results of this trial prove beneficial, the patient is referred to a neurosurgeon who implants the intrathecal baclofen pump system.2

multiple sclerosis Deep Brain Stimulation
Deep brain stimulation procedure educational explanation outline diagram. DBS process example with head surgical neurostimulator electrodes implantation vector illustration. Disorders treatment scheme. Credit: Getty Images

Deep Brain Stimulation

A deep brain stimulator is a device implanted by a neurosurgeon into a patient’s chest. The device connects to electrodes placed near the thalamus in the brain and transmits electrical impulses to disrupt the brain’s abnormal signaling that causes involuntary movements like tremors. Around 60% of patients with MS experience tremors.2,7 The patient controls the strength of the shocks sent by the device to their brain by adjusting it externally. They can even turn it off to make sure it does not interfere with other treatments.7

While deep brain stimulation may reduce MS symptoms, the implantation of such a device carries an increased risk of headaches, brain hemorrhage, stroke, infection, and device malfunctioning.2

A meta-analysis published in 2020 revealed level III evidence (randomized controlled trials) that deep brain stimulation improved MS-related tremors according to standardized tremor severity scales.8 

Rhizotomy, Neurectomy, and Radiosurgery

A physician may recommend a rhizotomy for patients with MS who have severe nerve pain or spasticity, particularly when these symptoms affect the head or face.7,9 Less than 5% of patients with MS experience trigeminal neuralgia, an extremely painful condition that triggers severe pain in the face.2

A rhizotomy is a surgical procedure that destroys nerve fibers in various ways, including radiofrequency to burn the nerve fibers, chemical injections of glycerin/glycerol to destroy the nerve, or surgical severing of the nerve fibers during selective dorsal rhizotomy.2,10 

multiple sclerosis radiosurgery
Gamma knife is a device used to treat brain tumors with a high dose of radiation (201 cobalt-60 sources) therapy in one day. The gamma knife device placed in circular array in heavily shielded assembly. The device aims gamma radiation through a target point in the patient’s brain. Credit: Getty Images

Selective dorsal rhizotomy is a type of rhizotomy in which the portion of a sensory nerve extending from a muscle into the spinal cord is severed, disrupting motor nerve signaling. This results in decreased pain, spasming, and spasticity in affected muscles.3,10

Rarely, neurectomies (ie, severing peripheral nerves) are performed to disrupt nerve signals to reduce pain and spasms. Rhizotomies and neurectomies are considered when other treatment options are ineffective in managing spasticity caused by MS.3   

Radiosurgery, also known as the Gamma Knife, CyberKnife, or X-Knife, is not technically an invasive surgical procedure. Radiosurgery uses radiation to selectively damage nerve fibers or parts of the brain, specifically the trigeminal nerve to treat trigeminal neuralgia and the thalamus to treat tremors. It is the least invasive procedure for MS-related trigeminal neuralgia.2 

Other surgical procedures that treat trigeminal neuralgia include microvascular decompression in the posterior fossa and Gasserian ganglion percutaneous techniques as alternatives to carbamazepine and oxcarbazepine, two sodium-channel blockers that cause sedative and motor side effects.11

MS Gastrostomy
PEG application is the process of feeding a tube to the stomach by endoscopy in patients who cannot eat by mouth. Credit: Getty Images

Gastrostomy

Approximately one-third of people with MS struggle with dysphagia. Dysphagia may decrease quality of life, increase the risk of aspiration pneumonia, and cause dehydration and malnutrition, necessitating the surgical insertion of a gastrostomy tube to safely provide nutritional support.12,13 

During a percutaneous endoscopic gastrostomy (PEG) procedure, a flexible, thin feeding tube is inserted into the stomach through the skin of the upper abdomen. Complications include tube blockages, infection, pain, and leakage of stomach contents.2

One study showed that the placement of a gastrostomy tube improved the median survival rate of 53 patients with MS by 2 years or longer. Those who underwent gastrostomy tube placement prior to the age of 50 years had a better chance of living longer.12,13 

References

  1. What is MS? National Multiple Sclerosis Society. Accessed May 11, 2022.
  2. Surgeries and procedures for multiple sclerosis. WebMD. Accessed May 11, 2022.
  3. Chang E, Ghosh N, Yanni D, Lee S, Alexandru D, Mozaffar T. A review of spasticity treatments: pharmacological and interventional approaches. Crit Rev Phys Rehabil Med. 2013;25(1-2):11-22. doi:10.1615/CritRevPhysRehabilMed.2013007945
  4. Intrathecal baclofen pump. Cleveland Clinic. Accessed May 11, 2022.
  5. FDA approves movement disorder drug from CNS therapeutics: Gablofen® (baclofen Injection) for the treatment of severe spas. News release. CNS Therapeutics; November 23, 2010.
  6. Rawlins PK. Intrathecal baclofen therapy over 10 years. J Neurosci Nurs. 2004;36(6):322-327. doi:10.1097/01376517-200412000-00005
  7. Johnson J. What to know about surgery for MS. Medical News Today. June 13, 2019. Accessed May 11, 2022.
  8. Brandmeir NJ, Murray A, Cheyuo C, Ferari C, Rezai AR. Deep brain stimulation for multiple sclerosis tremor: a meta-analysis. Neuromodulation. 2020;23(4):463-468. doi:10.1111/ner.13063
  9. Treatment options for severe spasticity due to multiple sclerosis. Medtronic. Accessed May 11, 2022.
  10. About selective dorsal rhizotomy (SDR). St. Louis Children’s Hospital. Accessed May 11, 2022.
  11. Di Stefano G, Maarbjerg S, Truini A. Trigeminal neuralgia secondary to multiple sclerosis: from the clinical picture to the treatment options. J Headache Pain. 2019;20(1):20. doi:10.1186/s10194-019-0969-0
  12. Figueiredo M. MS patients needing feeding tubes may live longer if given before age 50, study finds. Multiple Sclerosis News Today. February 13, 2020. Accessed May 11, 2022.
  13. Grandidge L, Chotiyarnwong C, White S, Denning J, Nair KPS. Survival following the placement of gastrostomy tube in patients with multiple sclerosis. Mult Scler J Exp Transl Clin. 2020;6(1):2055217319900907. doi:10.1177/2055217319900907

Reviewed by Harshi Dhingra, MD, on 5/16/2022.

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