MESA Rail™ AIS Study - Preservation of Curve Correction

Preservation of Thoracic Kyphosis and Coronal Curve Correction as a Function of Rod Stiffness in the Surgical Treatment of Adolescent Idiopathic Scoliosis (AIS) With the Use of the K2M MESA Rail™ Deformity System

To evaluate the restoration and maintenance of thoracic kyphosis and coronal curve correction demonstrated through the surgical implantation of the K2M MESA Rail™ Deformity System as compared to literature reported outcomes for standard Cobalt Chrome (CoCr) rod systems in the treatment of Adolescent Idiopathic Scoliosis (AIS).

Patients treated with the Ø5.5mm or Ø4.5mm MESA Rail™ Deformity System that had:

Diagnosis of AIS requiring surgical treatment for selective non-cervical fusion with a minimum of five (5) instrumented vertebrae between T1-S1 as confirmed by patient history and radiographic studies.

AIS cases must be classified as a Lenke type 1 or type 2 curve (lumbar modifiers and thoracic sagittal profiles will be noted but not restrictive).

Age at time of surgery of ≥ 11 years old and ≤ 21 years old.

Inclusion Criteria:

• Diagnosis of AIS requiring surgical treatment for selective thoracic/lumbar fusion with a minimum of five (5) instrumented vertebrae between T1-S1 as confirmed by patient history and radiographic studies. AIS cases must be classified as a Lenke type 1 or type 2 curve. No cervical vertebrae are to be incorporated into the construct.
• Willingness and ability to comply with the requirements of the protocol including follow-up requirements.
• Willing and able to sign a study specific informed consent form or, in the case of a patient who is a minor, provide assent and the minor patient's parent/legal guardian provides written consent to participate.
• Age range of ≥ 11 years old and ≤ 21 years old at time of surgery.

Exclusion Criteria:

• Previous anterior or posterior spine surgery at the index levels.
• Previous posterior spine surgery (e.g., posterior element decompression) that destabilizes the cervical/thoracic/lumbar spine.
• Active systemic infection or infection at the operative site.
• Co-morbid medical conditions of the spine or upper/lower extremities that may affect the thoracic or lumbar spine neurological and/or pain assessment.
• Metabolic bone disease such as osteoporosis that contradicts spinal surgery.
• History of an osteoporotic fracture.
• History of an endocrine or metabolic disorder (e.g., Paget's disease) known to affect bone and mineral metabolism.
• Taking medications that may interfere with bony/soft tissue healing including chronic steroid use.
• Known allergy to titanium or cobalt chrome.
• Rheumatoid arthritis or other autoimmune disease or a systemic disorder such as HIV, active hepatitis B or C or fibromyalgia.
• Insulin-dependent type 1 or type 2 diabetes.
• Medical condition (e.g., unstable cardiac disease, cancer) that may result in patient death or have an effect on outcomes prior to study completion.
• Pregnant, or intend to become pregnant, during the course of the study.
• Severe obesity (Body Mass Index > 40).