Compounds of Formula and salts thereof:wherein:M is 2H, Si, a metal, an oxymetal group, a hydroxymetal group or a halometal group;Pc represents a phthalocyanine nucleus of formula;R1 is H or optionally substituted C1-4alkyl;R2 is H or optionally substituted hydrocarbyl;R3 is H or optionally substituted C1-4alkyl;R4 is H or optionally substituted hydrocarbyl;x is 0. It may be used for dynamic stabilization of the spine. Obtaining, with the processor, second data recorded with a second monitoring device, the second data including second research data that includes the first omitted data, the second data recorded at the first time.