The purpose of this study is to determine if Plexur P grows bone in the iliac crest (where bone was removed or "harvested") for the back surgery.

The study will be focusing on patients who require back surgery. Often additional bone is required from the hip of the patient (iliac crest). When bone removed from the hip, a "void" is often created. This "void" will be filled in with Osteotech's Plexur P product.

This prospective trial is designed to evaluate the ability of the Plexur P device (bone void filler) to reconstitute the iliac crest in patients requiring iliac crest bone harvesting procedures at one single study site.

Plexur P Bone Void Filler is:

• A biocomposite of mineralized cortical allograft bone fibers and polylactide-co-glycolide co-polymer.
• Designed to fill bony voids or gaps of the skeletal system that are not intrinsic to the stability of the bony structure.
• Porosity is introduced into the Plexur P Biocomposites to create a cancellous-like structure that provides a scaffold for bone growth.

In addition:

• Patients will be screened for study eligibility based on the need for iliac crest bone harvesting.
• Fifteen (15) eligible patients will be enrolled and will have an iliac crest harvesting defect backfilled with Plexur P to repair the iliac crest defect.
• As a part of routine follow up care, patient related outcomes including measurements of pain severity and pain relief will be determined using patient (IRB approved) questionnaires.
• Radiographic analysis will also be used to determine amount of bony ingrowth of the Plexur P device.

Inclusion Criteria:

• The patient is at least 18 yrs old.
• The patient requires an iliac crest harvesting procedure.
• The patient has signed an Informed Consent, approved by the IRB.

Exclusion Criteria:

• Patient is less than 18 years old.
• Patient presents with a bony void or gap in an area other than the iliac crest and/or has an infection present at the (operative) site.
• Insulin dependent diabetics and/or in the opinion of the investigator, has poorly controlled non-insulin dependent diabetes.
• The patient is a smoker.
• The patient is mentally compromised (e.g., currently being treated from a psychiatric disorder, senile dementia, Alzheimer's disease, etc.) and/or in the opinion of the investigator, is not likely to complete follow up visits;
• The patient has a bleeding disorder of any etiology, severe vascular or neurological disease;
• The patient has hypercalcemia and/or severe degenerative bone disease;
• The patient has a history of long term steroid use;
• The patient requires immunosuppressive therapy;
• The patient has a history of drug or alcohol abuse that may interfere with his/her ability to provide written informed consent;
• The patient is pregnant at the time of study entry or may likely become pregnant during the course of study participation;
• The subject has an implanted device, which is incompatible with the use of imaging equipment;
• The patient has an allergy to one of the components of the investigational device;
• The patient has renal insufficiency;
• The patient has a terminal illness.