Revision Spine Surgery: A systematic approach.
Revision spine surgery is a complex undertaking with variable prognosis. A systematic approach to dealing with revision procedures eliminate much of the unpredictability and ultimately improves outcome. There are multiple factors contributing to surgical failure including
- poor patient selection
- inadequate conservative treatment
- postoperative instability
- recurrent herniation
- patient co-morbidities often affect the patient’s outcome and appropriate expectation management is necessary in these situations
ASSESSING FAILED SURGICAL PROCEDURE
When assessing a failed surgical procedure, one needs to look back at the records in a comprehensive fashion.
- Analysis of the specific symptoms, neurologic findings and patient factors is important when assessing the indications for the initial procedure.
- An analysis of the conservative care provided and the responses obtained also provide insight into the future outcome.
- A review of the specific treatments including physical therapy, medication, chiropractic and psychosocial factors are important in assessing the risk for failure.
When assessing a failed discectomy type procedure there are several important questions to ask.
- The side of the symptoms and the specific dermatomal distribution of neurologic complaints are critical. Occasionally, wrong level surgery occurs which can lead to an obvious poor outcome postoperatively.
- Critical evaluation of the imaging studies is necessary to establish the diagnosis at the time of the procedure and to correlate with postoperative imaging studies.
- Flexion/extension radiographs before and after surgery are important to assess for instability which may complicate surgical treatment.
- It is important to ask whether there was a period of symptom resolution before the recurrence of pain. This can help establish the differential between a retained or recurrent disc herniation.
- One needs to ask if symptoms are the same or somewhat different from prior to the first procedure.
- Postoperative MRI should be obtained with contrast to help differentiate scar tissue from recurrent disc herniation. As always, quality imaging is extremely important.
FORMULATING TREATMENT PLAN
Once the postoperative imaging studies are reviewed, a treatment plan can be formulated. If the symptoms have recurred without a recurrent disc herniation, an aggressive therapy program, medical management and occasionally injections are appropriate to bring about symptom resolution. If progressive degeneration of the disc occurs, a surgical fusion may ultimately be necessary. A single recurrence may be treated with a repeat discectomy. Multiple recurrences often require spinal fusion to restore stability in addition to nerve decompression.
Failure of the fusion process is often multifactorial. Patient co-morbidities are often significant and the ultimate outcome of these procedures. Obesity, deconditioning, depression, work-related issues and litigation are strong factors that ultimately affect the outcome in a negative sense. The importance of sound surgical technique is often underestimated. The promotion of minimally invasive techniques which often compromise the decompression and exposure for performance of the fusion may lead to higher pseudoarthrosis rates.
USE OF IMAGING STUDIES—MRI, CT
The imaging studies are critical when assessing a failed fusion. Postoperative MRI imaging is helpful in assessing for recurrent disc herniation and at times adjacent level stenosis. MRI is not useful in assessing the status of a fusion. A good quality CT scan with reconstruction images is the most reliable method to assess for the status of a spinal fusion. The soft tissue and bone windows on the CT are helpful in establishing the presence of residual stenosis, heterotopic bone and hardware position. Standing radiographs with attention to sagittal balance and stability are important as well.
SURGICAL RESPONSE TO FAILED FUSION
The surgical reconstruction of a failed fusion often involves implant removal, resection of scar tissue, decompression of residual stenosis and possibly osteotomy for restoration of sagittal balance. A combination of approaches is necessary at times to achieve appropriate reconstruction. Access to the anterior column of the spine is often necessary; therefore, a relationship with a good vascular surgeon is mandatory in developing a successful revision spinal surgery practice.
PERIOPERATIVE & POSTOPERTIVE CARE
Even when one has a team of surgical experts to perform the technical component of the reconstruction, the perioperative critical care team and nursing team is essential to attaining good outcomes. These reconstructions are associated with greater blood loss and systemic stresses that require intense medical management. Perioperative and postoperative narcotic management with an experienced pain management program are mandatory. Many patients have been on narcotics for years and have significant tolerance issues to deal with in addition to the surgical reconstruction. A comprehensive approach to pain management achieves the greatest outcome.
Managing revision spinal surgery is a complex multidisciplinary aspect of spinal surgery associated with higher complication rates and relatively poor outcomes when compared to primary surgery. Nonetheless, clinical success has often been achieved in my surgical practice. Management of expectations combined with sound surgical technique and pain management does indeed produce a great deal of clinical success. Careful follow-up and prompt management of complications leads to consistent improvement in these patients’ quality of life. Achieving clinical success and improved functional outcome is often the most rewarding aspect of my practice.