G2144 HCPCS - FUNCTIONAL STATUS MEASURED BY THE OSWESTRY DISABILITY INDEX (ODI VERSION 2.1A) AT THREE MONTHS (6-20 WEEKS) POSTOPERATIVELY WAS LESS THAN OR EQUAL TO 22 OR FUNCTIONAL STATUS MEASURED BY THE ODI VERSION 2.1A WITHIN THREE MONTHS PREOPERATIVELY AND AT THREE MONTHS (6-20 WEEKS) POSTOPERATIVELY DEMONSTRATED AN IMPROVEMENT OF 30 POINTS OR GREATER