Low-Dose Radiation to Prevent Complications of Back Surgery
Condition: Failed Back Surgery Syndrome; Postlaminectomy Syndrome; Postdiscectomy Epidural Fibrosis
MeSH terms: Syndrome; Fibrosis; Failed Back Surgery Syndrome
Study type: Interventional
Phase: Phase 1

Summary: 
      More than 10,000 people each year in the United States have "failed back surgery syndrome"
      caused by scars that form around the outer surface of the spinal cord. Such scarring, known
      as peridural fibrosis, is common after back surgery known as either lumbar discectomy or
      laminectomy. Peridural fibrosis may cause recurring low back pain or leg pain after surgery.
      Operating again to remove the scar tissue often leads to more scarring.

      Researchers have not previously studied radiation as a way to prevent peridural fibrosis. We
      will test whether low-dose radiation given 24 hours before surgery will decrease the amount
      of peridural fibrosis and if this reduction will lead to improved results of surgery. Half of
      the participants will receive radiation before surgery and the other half will not. We will
      evaluate patients at followup visits 1, 3, 6, and 12 months after surgery with a physical
      exam and questionnaire. At 12 months, we will obtain magnetic resonance imaging (MRI) of the
      lower spine.
    

Detailed description: 
      Researchers have long known that low-dose radiation inhibits fibroblast and osteoblast
      activity. Studies in humans have shown that perioperative radiation therapy is a useful way
      to prevent both keloid and heterotopic bone formation. However, researchers have not
      previously studied radiation as a means to inhibit peridural fibrosis. Our previous studies
      of both rat and dog models showed a significant reduction in peridural fibrosis after
      laminectomy using low-dose external beam radiation (700 cGy) given 24 hours prior to surgery.
      Based on our results from these animal studies, we will test whether (1) low-dose radiation
      given 24 hours before surgery will decrease the amount of peridural fibrosis in people and
      (2) this reduction in peridural fibrosis will lead to improved results of surgery.

      For this study, we will enroll 46 patients with failed back surgery syndrome believed to be
      secondary to perineural fibrosis in a randomized, double-blinded, controlled clinical trial.
      We will assign patients to one of two groups before surgery: preoperative radiation
      (treatment group) or no preoperative radiation (control group). We will treat half of the
      patients with external beam radiation before re-exploration and decompression of their
      peridural fibrosis (treatment group) and perform re-exploration and decompression in the
      other half without preoperative radiation (control group).

      All patients will undergo simulation radiation treatment planning and will not know if they
      received radiation or not. For patients randomized to receive preoperative radiation, we will
      administer a single dose of 700 cGy to a 6.0-cm-wide field centered on the spinal cord at the
      affected level, using a 6 MV Varian 600C linear accelerator. We will administer treatment
      with two fields angled 45 degrees from the vertical plane so that the skin surface for the
      proposed incision will not be irritated. This should prevent any wound healing problems. Only
      the radiation oncologist and research assistant will know whether radiation was administered.
      The patient and the surgeon will be masked as to the treatment.

      The neurosurgeon co-investigators will perform the same surgical procedure on all patients 24
      hours after their radiation (or sham) treatment. We will give all patients preoperative
      antibiotics. The surgeon will reopen the previous midline posterior lumbar skin incision and
      dissect the subcutaneous tissue away from the spinous process and laminae. Once the surgeon
      has adequately exposed the previous surgical site, he or she will place a self-retaining
      retractor. The surgeon will decompress the nerve by removing the scar tissue from around the
      nerve root and thecal sac. The surgeon will also remove any intravertebral disc material
      thought to be causing nerve root compression. On completion of the operation, the surgeon
      will stop bleeding with electrocautery, irrigate the wound with antibiotic, and close the
      wound in layers. In general, the hospital stay after surgery is one night. The patient begins
      gradual ambulation on the evening of surgery.

      We will administer the North American Spine Society (NASS) Lumbar Spine Outcome Assessment to
      patients before treatment and at followup visits to assess their physical functioning. We
      will also use the NASS questionnaire to collect demographic and lifestyle information at
      baseline and to assess patient expectations regarding treatment and level of satisfaction
      with the treatment during the followup period. We will do a physical examination and
      administer the patient-reported questionnaire prior to surgery and at 1, 3, 6, and 12 months
      after surgery. We will obtain magnetic resonance (MR) imaging of the lumbar spine 12 months
      after treatment.
    

Intervention name(s): Lumbar nerve root decompression; Preoperative low-dose external beam radiation
Intervention type(s): Procedure; Procedure
Allocation: Randomized
Intervention model: Single Group Assignment
Masking: Double
Primary purpose: Treatment
Keywords: Epidural fibrosis; Failed back surgery syndrome; Postlaminectomy syndrome; Lumbar laminectomy; Radiotherapy; Radiation; Perineural scar formation; Peridural fibrosis; Back surgery