Long-Term Outcomes for Lumbar Spinal Stenosis Patients Treated With X STOP®

Evaluate the long term safety and effectiveness of the X-Stop interspinous process
decompression system In the patients who received the X-Stop under the IDE. These patients
consist of two cohorts to be evaluated: patients who had moderately impaired physical
function prior to X-Stop implantation (as determined by a baseline score >2.0 in the physical
function (PF) domain of the Zurich claudication questionnaire), and patients who had mildly
impaired physical function prior to X-Stop surgery(as determined by a baseline score <=2.0 in
the PF domain of the Zurich claudication questionnaire (ZCQ), through the fifth postoperative
year. Clinical examination will be performed at each office visit to confirm the absence of
neurological complications. X-ray films (AP/lateral views) taken during the fifth
postoperative year will, be analyzed to confirm A) maintenance of distraction and B) the
absence of radiological evidence of device-related complications. Secondary endpoints will
include mean scores from the SF-36, and incidence rates of adverse events, device failures,
and secondary surgeries.

Inclusion Criteria:

A patient will be admitted into the LTOS program if he/she meets all of the following
inclusion criteria:

1. Completed participation in the Pivotal Trial, CAP, or COS and has the X STOP
implant(s) intact at the time of LTOS enrollment; OR is an active CAP/COS participant,
has the X STOP implant(s) intact, and has not completed a 24-month follow-up visit in
his/her CAP/COS study.

2. Is willing and able to provide Informed Consent

3. Is willing and able to return to the clinic for a clinical evaluation or complete
study questionnaires without a clinic visit.

Exclusion Criteria:

A patient will not be admitted into the LTOS program if he/she meets any of the following
exclusion criteria:

1. Participated in the Pivotal Trial as part of the X STOP group, but the device has been
removed.

2. Participated in the CAP or COS programs, but the device has been removed.