UNKNOWN INTERBODY DEVICE

Description of Event or Problem

IT WAS REPORTED IN A PUBLICATION THAT THE AUTHORS CONDUCTED A PROSPECTIVE COHORT STUDY OF ALL PATIENTS IN THE STUDY PERIOD UNDERGOING INSTRUMENTED TLIF. THIS STUDY INCLUDED 81 PATIENTS (40 MEN AND 41 WOMEN) WITH A MEAN AGE OF 43.5 YEARS (RANGE 20¿64 YEARS) WHO UNDERWENT INSTRUMENTED TLIFS BETWEEN JANUARY 2005 AND MAY 2006. GROUP I (37 PATIENTS) HAD CARBON FIBER CAGES PLACED WHILE GROUP II (44 PATIENTS) HAD 70/30 PLDLA CAGES IMPLANTED. PLAIN RADIOGRAPHS WERE OBTAINED AT 6 WEEKS, 3 MONTHS, 6 MONTHS, AND 1 YEAR TO ASSESS ARTHRODESIS. PATIENTS WERE FOLLOWED FOR 24¿39 MONTHS. INFORMATION ON PATIENT DEMOGRAPHICS AND COMPLICATIONS DURING THE FOLLOW-UP PERIOD WAS RECORDED AND ANALYZED. PATIENTS UNDERWENT 1- AND 2-LEVEL TLIFS FOR ONE OR MORE OR THE FOLLOWING DIAGNOSES: DDD, SCOLIOSIS, AND SPONDYLOLISTHESIS. THREE-LEVEL TLIFS WERE PERFORMED IN 2 PATIENTS WITH SCOLIOSIS. ONE LARGE KIT OF RHBMP-2/ACS WAS DIVIDED INTO 1 SMALL PIECE AND 2 EQUAL BUT LARGER PIECES. THE SMALL PIECE OF INFUSE WAS PACKED INTO EITHER THE HYDROSORB BIODEGRADABLE PLDLA CAGE OR THE LEOPARD CFRP TLIF CARBON FIBER CAGE (DEPUY SPINE) CAGE. ONE CAGE PER LEVEL WAS THEN INSERTED INTO THE DISC SPACE. INTRAOPERATIVE FLUOROSCOPY WAS USED TO VERIFY APPROPRIATE PLACEMENT OF THE CAGE. BILATERAL SEGMENTAL PEDICLE SCREW FIXATION AND FUSION WAS PERFORMED WITH POSTERIOR TITANIUM SCREWS AT A VARIABLE NUMBER OF LEVELS ABOVE AND BELOW THE LEVEL OF THE TLIF. THE SPONGE WAS PLACED INTO THE INTERBODY CAGE, AND THE REST OF THE 12-MG SPONGE WAS DIVIDED EQUALLY AND WAS PLACED BILATERALLY ON THE DECORTICATED TRANSVERSE PROCESSES. NO ADDITIONAL BMP-2 WAS PLACED IN THE DISC SPACE OUTSIDE OF THE CAGE. A DRAINAGE TUBE WAS PLACED SUBFASCIALLY, AND A MULTILAYER WOUND CLOSURE WAS PERFORMED. FUSION WAS ASSESSED ON LATERAL FLEXION-EXTENSION FILMS BY THE PRESENCE OR ABSENCE OF MOTION BETWEEN 2 ADJACENT FUSION SEGMENTS AND ON ANTEROPOSTERIOR AND LATERAL RADIOGRAPHS BY THE PRESENCE OF NEWLY FORMED TRABECULATED BONE BETWEEN 2 ADJACENT FUSION SEGMENTS. PATIENTS WERE GIVEN THE DIAGNOSIS OF PSEUDOARTHROSIS AFTER 1 YEAR IF PROGRESSIVE BONY HEALING HAD NOT BEEN NOTED ON THE SUCCESSIVE RADIOGRAPHS. EIGHT PATIENTS IN GROUP 1 DEVELOPED POSTSURGICAL CAGE MIGRATIONS. THESE PATIENTS USUALLY PRESENTED WITH SEVERE, UNREMITTING BACK AND/OR LEG PAIN. THREE PATIENTS WITH POSTSURGICAL MIGRATION WERE ALSO NOTED TO HAVE PSEUDOARTHROSIS.

Additional Manufacturer Narrative

ARTICLE CITATION: SMITH ET AL. INCREASED INCIDENCE OF CAGE MIGRATION AND NONUNION IN INSTRUMENTED TRANSFORAMINAL LUMBAR INTERBODY FUSION WITH BIOABSORBABLE CAGES. J NEUROSURG SPINE 13:388¿393, 2010. DEVICE NAME: HYDROSORB BIODEGRADABLE PLDLA CAGE. (B)(4). NEITHER THE DEVICE NOR FILMS OF APPLICABLE IMAGING STUDIES WERE RETURNED TO THE MANUFACTURER FOR EVALUATION. THEREFORE, WE ARE UNABLE TO DETERMINE THE DEFINITIVE CAUSE OF THE REPORTED EVENT. PRODUCTS FROM MULTIPLE MANUFACTURERS WERE IMPLANTED DURING THE PROCEDURE. ALTHOUGH IT IS UNKNOWN IF ANY OF THE DEVICES CONTRIBUTED TO THE REPORTED EVENT, WE ARE FILING THIS MDR FOR NOTIFICATION PURPOSES.