GRASSP: Gralise® for Spine Surgery Pain (GRASSP)

Inclusion Criteria.

1. Male and female subjects age 18 to 80 years.
2. Primary diagnosis of post-laminectomy pain syndrome (PLPS), defined as having their most severe pain related to a prior history of lumbar surgery including decompressive (e.g. laminectomy) or fusion (e.g. posterior lumbar interbody fusion) procedures performed from the L1-S1 level at least 6 months prior to enrollment.
3. Pain Detect score ≥12, denoting neuropathic pain is probable.
4. At least 50% of present pain intensity is attributed to the lower extremity (Quebec Task Force Grade 3 or 4) on most days.
5. All subjects must be decisionally capable and must give their own consent to be enrolled.

Exclusion Criteria.

1. Lumbar surgery <6 months prior to enrollment
2. Subjects with PLPS and pain free interval (defined as chronic low back pain and radicular symptoms <=3/10) related the indication for their PLPS defining event and a new, acute or subacute symptom pattern (e.g. new disc herniation at an adjacent level as documented by imaging).
3. Subjects regularly taking gabapentin or pregabalin for their chronic pain after spine surgery who do not endorse relief (defined as either minimally, much or very much improved on a 7 point likert scale when asked about these medications' effects).
4. Having another type of pain that is as or more severe than pain associated with PLPS.
5. An average daily pain score of 10 on the NRS scale during either the screening or initial washout period.
6. Concurrent medication that includes antiepileptic drugs (AEDs) (exceptions: pregabalin or gabapentin).
7. Subjects taking concomitant neuropathic pain medication (stable dose for at least 4 weeks) may reduce the number and/or dose of their current pain medications: If the number and/or dose exceed the limits of allowed neuropathic pain medications (refer to Use of Allowed Pain Medication), then the number and/or dose must be reduced to fall within acceptable limits. Concomitant neuropathic pain medication needs to be kept stable during the study.
8. Subjects who have previously not responded to treatment with gabapentin at doses of ≥900 mg/day or pregabalin at doses ≥300 mg/day.
9. Known hypersensitivity to Gralise, or gabapentin, or its ingredients.
10. Dose limiting adverse events to gabapentin; subjects who previously experienced dose-limiting adverse effects that prevented titration of gabapentin to an effective dose.
11. History of alcohol and/or drug abuse in the investigator's judgment, based on subject history and physical examination.
12. Subject who consumes excessive amounts of alcohol, defined as greater than 3 glasses of alcoholic beverages (1 glass is approximately equivalent to: beer [10 ounces], wine [4 ounces], or distilled spirits [1 ounce]) per day on a regular basis.
13. Participation in a clinical trial of an investigational drug or device within 30 days of the screening visit.
14. Gastric reduction surgery.
15. Acute gastrointestinal symptoms such as diarrhea, dyspepsia, or gastric or duodenal ulcers.
16. Malignancy within past 2 years other than basal cell carcinoma.
17. Women who are pregnant or breastfeeding.
18. History of seizure or is at risk of seizure due to head trauma.
19. History of significant cardiovascular, respiratory, endocrine, liver or kidney disease (subjects with renal impairment or creatine clearance <30 ml/min).
20. Any significant medical condition, laboratory abnormality, or psychiatric illness (e.g. depression, mood problems, suicidal thoughts) that would prevent the subject from participating in the study.