Physicians Recommend Early Surgery to Correct Spinal Issues in MPS Patients

Spinal cord decompression — a type of spinal surgery — should be done on mucopolysaccharidosis (MPS) patients who have lesions in their spine to prevent or reverse neurological issues, a study shows.

The study, “Clinical Manifestations and Surgical Management of Spinal Lesions in Patients With Mucopolysaccharidosis: A Report of 52 Cases,” was published in the journal Spine Deformity.

MPS is group of genetic diseases characterized by a deficiency in enzymes involved in the degradation of large molecules known as glycosaminoglycans (GAGs). Depending on the type of enzyme affected, different clinical manifestations and syndromes will emerge.

The progressive accumulation of GAGs inside lysosomes — the cell compartments responsible for digesting and recycling substances — causes issues in various organs including the liver, spleen, eye, cardiovascular, and central nervous system. As a result, patients have a wide variety of clinical symptoms.

Spinal lesions are among the clinical manifestations of MPS. Classic spinal lesions associated with MPS are normally detected between 18 and 24 months of age.

Due to the frequency of these lesions in MPS patients, researchers set out to describe the clinical manifestations, imaging findings, and surgical management of spinal lesions in the largest group of pediatric MPS patients with a surgically treated spinal condition to date.

Researchers conducted a retrospective study of 52 pediatric patients (32 males; 20 females) who were diagnosed with MPS between 1992 and 2011 and were followed at a single spine center of a pediatric hospital. Of the patients, 14 were diagnosed with MPS type I, 11 with MPS type II, three with MPS type III (or Sanfilippo syndrome), 23 with MPS type IV, and one with MPS type VI.  Mean age at diagnosis was 8 years, with a range of 1-19 years.

Patients were evaluated at the beginning of the study and during follow-up, and information on demographics, clinical manifestations, spinal cord lesions, and surgical management were recorded.

“The children had regular clinical and radiographic examination at the sixth week, third month, sixth month, and annually during follow-up [mean 11 years] after surgery,” the researchers wrote.

Two spinal regions were found to be mainly affected at the start of the study — the cervical and the thoracolumbar region. Forty-three patients demonstrated disease involvement in the cervical region, which is the neck region of the spine involved in protecting the brain stem (the lower part of the brain) and the spinal cord, supporting the skull, and allowing for a wide range of head movement.

Fourteen patients had involvement of the thoracolumbar region, which is the junction at which the thoracic (longest region of the spine and attached to the ribcage) and lumbar regions (the lower spinal region) meet.

Surgery was performed in 38 patients, 25 of whom had cervical spine involvement and 13 had thoracolumbar spine involvement. Of these patients, 28 required spinal fusion surgery — a surgical procedure used to correct problems with vertebrae, the small bones in the spine.

Of those who had surgery, 21 exhibited neurological manifestations, which refers to neurological signs and symptoms that are caused by a disease or injury that is not primarily neurological (such as MPS). Quadriparesis — a condition characterized by weakness in all four limbs — was the most frequent neurological manifestation.

Among these patients with neurological manifestations, six patients showed neurological improvement after surgery.

The most common surgical complication was proximal junctional kyphosis, a common complication that develops in 39% of adults following surgery for spinal deformity.

Because spinal deformities were found to be very common in these patients, the researchers encouraged a “multidisciplinary assessment and an early evaluation of the cervical spine in these patients.”

Additionally, they recommended that MPS patients with spinal lesions undergo early spinal cord decompression — a surgery that can help relieve pressure in the spinal cord and restabilize the spine — associated with arthrodesis (surgical immobilization of a joint by fusion of the nearby bones) and intraoperative somatosensory evoked potential and motor evoked potential — a process that helps prevent or potentially reverse neurological impairment.

While these surgical procedures generate good results with regards to the rate of correction and spinal fusion in medium-and long-term follow up, the authors add that “meticulous presurgical planning and surgeon expertise are mandatory.”