Pedicle Osteotomy for Stenosis Trial

LSS is a narrowing of the spinal canal and/or the intervertebral foramina by bony spurs or
soft tissues that decrease space for the neural elements resulting in compression of the
nerve roots or spinal cord in the lumbar region of the spine. LSS can cause low back pain,
weakness, numbness, and pain and loss of sensation in the buttocks and legs. In most cases
the symptoms improve when the patient is sitting or leaning forward, due to the flexed
position of the vertebra which leads to reduced impingement of the neural tissue. In
addition, many patients with LSS complain of pain when standing and walking referred to as
neurogenic intermittent claudication (NIC). Nonsurgical management is well-established as the
first-line treatment approach for LSS patients with mild to moderate symptoms. It typically
involves the prescription of modified physical activity, physiotherapy, anti-inflammatory
drugs, epidural steroid injections, use of a lumbar corset or some combination thereof.

Surgical treatment is reserved for patients who do not obtain adequate relief of symptoms by
conservative management. The goal of surgical treatment for LSS is to relieve the compression
of the spinal nerves in the spinal canal or neural foramina. Such decompressive surgery
generally involves laminectomy, laminotomy, foraminotomy, partial facetectomy or some
combination thereof. Decompressive surgery in subjects with LSS and spondylolisthesis
commonly requires fusion to stabilize the spondylolisthesis. The most commonly performed
lumbar fusion for patient's with the combination of LSS and spondylolisthesis is a
Transforaminal Lumbar Interbody Fusion (TLIF) which involves stabilizing the motion segment
by placing pedicle screws, rods and an interbody fusion cage. Autograft or allograft bone are
commonly used to bring about fusion or a bridging of bone across the intervertebral joint.

The Altum® Pedicle Osteotomy System contains the implants and instruments required to perform
the pedicle lengthening osteotomy procedure for the treatment of LSS. The Altum® implant is
an expandable bone screw that is available in a variety of sizes (7.5 mm, 8.5 mm and 9.5 mm).
Altum® instruments are manufactured from IXEF PARA GS-1022 GY/51, medical grade titanium
alloy (Ti 6AL-4V ELI ASTM F-136), and medical grade stainless steel (17-4 ASTM F899).

Inclusion Criteria:

1. Is a male or female patient between 40 and 80 years of age.

2. Has the diagnosis of degenerative spinal stenosis of the lumbar region (defined as
L2-L5), defined by one or more of the following: a) narrowingof the mid-sagittal
spinal canal (central stenosis), b) narrowing between the facet superior articular
process (SAP) and the posterior intervertebral disc margin (lateral recess stenosis),
c) narrowing of the nerve root foraminal canal(s) (foraminal stenosis) and has, at the
same level, radiographic confirmation on plain lateral flexion/extension radiographs
of a degenerative grade I spondylolisthesis at the same level, defined as at least 1%
but not greater than 25%, offset between the posterior margins of the adjacent
vertebral bodies at the index level.

3. Neurogenic claudication or radiculopathic symptoms including leg pain, muscle
weakness, and/or sensation abnormality, with or without back pain, which is worse with
extended posture and relieved by flexion, as evidenced by patient history.

4. Has pain in the leg and/or buttock that is worse with standing as compared to sitting.

5. Has radiographic confirmation on CT or MRI of moderate or greater lumbar spinal
stenosis at the index level defined as > 25% reduction in area of the central and/or
lateral recess and/or foraminal regions of the spinal canal as compared to the
adjacent level.

6. Has radiographic confirmation on CT or MRI of compression of the thecal sac and/or
cauda equina and/or nerve root(s) due to hypertrophy of the facet joints and/or
ligamentum flavum thickening/buckling

7. Has undergone a 6 month or longer course of conservative therapy without sufficient
relief of symptoms that has included one or more of the following interventions:
physical therapy, bracing, systemic and/or injected medications.

8. Has moderate or greater impairment on the Zurich Claudication Questionnaire (ZCQ)
Physical Function scale (PF) defined as a score of 2 or greater.

9. Has moderate or greater impairment on the Oswestry Disability Index defined as a score
of 30 or greater.

10. Is a surgical candidate for lumbar decompressive surgery at one or two levels in the
L2 through L5 region of the spine.

11. Is psychosocially, mentally and physically able to comply with all study procedures
required by the study protocol including attending all scheduled visits and
interventions.

12. Is able to provide voluntary, informed consent to participate in the clinical trial
and has signed the informed consent documents.

Exclusion Criteria:

1. Has had prior spinal surgery at any level between L1 and S1.

2. Requires more than 2 lumbar levels of surgical decompression.

3. Has a degenerative spondylolisthesis of greater than grade I defined as greater than
25% offset between the posterior margins of adjacent vertebral bodies on plain lateral
flexion/extension radiographs or does not have a grade I degenerative
spondylolisthesis, defined as 0% offset between the posterior margins of adjacent
vertebral bodies on a plain lateral flexion/extension radiograph.

4. Has more than one level of degenerative spondylolisthesis or has spondylolisthesis
located at lumbar levels which are not treated with surgical decompression. Has the
diagnosis of peripheral neuropathy.

5. Has a complete motor or sensory deficit.

6. Has a pars defect.

7. Has facet joints at the implant level that are absent or fractured.

8. Has lumbar scoliosis with a Cobb angle of greater than 25o.

9. Has a disc herniation at any lumbar level requiring surgical intervention.

10. Has symptomatic hip arthritis or hip pain.

11. Has a Body Mass Index (BMI) of greater than 40.

12. Has a known allergy to titanium or titanium alloys.

13. Has osteoporosis. The SCORE (Simple Calculated Osteoporosis Risk Estimation) will be
used to screen subjects who require DEXA; Subjects with T-score < -2.5 (per The World
Health Organization definition) will be excluded.

14. Has a history of Paget's disease, osteomalacia, or any other metabolic bone disease.

15. Has a history of rheumatoid arthritis or other systemic autoimmune disease.

16. Requires medications or drugs known to interfere with bone/soft tissue healing (e.g.,
chronic systemic corticosteroids). Corticosteroids used for 6 weeks or less are not an
exclusion criteria.

17. Has insulin dependent diabetes mellitus.

18. Has cauda equina syndrome, defined as neural compression in the lumbar spine causing
neurogenic bowel (rectal incontinence) or neurogenic bladder (bladder retention or
incontinence) dysfunction.

19. Only has axial back pain with no leg or buttock pain.

20. Has back or leg pain of unknown etiology.

21. Has evidence or the diagnosis of significant peripheral vascular disease (e.g.
diminished or absent dorsalis pedis or posterior tibial pulses)

22. The patient currently has any of the following: schizophrenia, bipolar disorder, major
depression, major psychotic disorder, and substance or alcohol abuse or dependency as
defined by the DSM V.

23. Has participated in a clinical trial of another investigational drug or device within
the past 2 years.

24. Has an active, chronic infection, either systemic or local.