Anderson 1999.

Methods	Case series Duration: 24 months
Participants	N = 30 enrolled Primary condition: Most had back and/or leg pain, In 47% associated with failed back surgery syndrome Baseline pain score: Mean 78.5 (SD 15.9, Range 39 to 100)/100 VAS Time since onset: 8 years (SD 9 years, Range 5 to 24 years) Mean age: 58 years (SD 13 years) Female: 53% Previous opioid analgesia: All patients had taken systemic narcotics before study enrolment, and 28/30 (93%) were taking them regularly at time of enrolment
Interventions	Intrathecal morphine Initial dose: Mean 1 mg/day Titration up to 25 mg/day at endpoint Supplemental analgesia: Allowed. At 24 months, 6/20 (30%) patients used supplemental oral narcotics
Outcomes	Discontinuation due to adverse events Adverse events Discontinuation due to insufficient pain relief Pain (continuous) and pain relief (proportion with at least 50% relief) Function
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Comparability of patients at baseline and follow‐up (continuous data) All outcomes	High risk	Due to attrition
Selection method random or consecutive	Low risk	Consecutive
Prospective	Low risk	Prospective
Free from confounding treatment(s)	High risk	Supplemental analgesia allowed
Patient compliance monitored and reported at at least 85%?	Low risk	Pump administration
Attrition and right censoring less than 15% (continuous data) All outcomes	High risk	Higher attrition
Funding from a source without financial conflict of interest?	High risk	Funding from Medtronic