Surgical decompression of the spinal cord is often carried out soon after injury and, in some cases, long after injury. Basically, with this surgery, various tissue or bone fragments that compress the spinal cord and, in turn, compromise cord function are removed. Depending upon the injury’s unique circumstances, decompression can be accomplished by a variety of surgical approaches, including, for example, approaching the compressed cord from either the front (anterior) or back (posterior).

Acute Injury

Although animal studies consistently suggest that spinal cord decompression soon after injury minimizes neurological damage, human studies have been more ambiguous, i.e., some studies suggest benefits and others do not.  Results seem to depend upon numerous factors, such as the nature of the injury, the timing of the surgery, and specific outcome measures.

Earlier studies, including those carried out by some of the pioneers of modern SCI medicine, suggested that conservative, non-surgical approaches (e.g., postural techniques,  bed rest, etc), were the best way to fuse the injured spine and would avoid exposing the patient to surgery-associated risks and neurological complications.

However, as spinal surgery became more sophisticated over time, minimizing its downside, the pendulum increasingly swung towards the widespread use of surgical decompression in acute SCI.

There has been a plethora of studies attempting to address the effectiveness of surgical decompression. For example, Dr. Stephen Papadopoulos et al (Michigan, USA) concluded that “immediate spinal column stabilization and spinal cord decompression…may significantly improve neurological outcome” (J Trauma 52(2), 2002). In their study, 91 consecutively admitted patients with acute cervical injuries were prospectively evaluated. Of these patients, 66 had potential spinal cord compression assessed by magnetic resonance imaging (MRI); if present (54% of patients), they underwent immediate surgical decompression and stabilization. For a variety of reasons, 25 patients were treated outside of this protocol (i.e., no surgical decompression) and served as a reference group.

The protocol-treated group fared better than reference patients on several criteria. For example, 50% of protocol patients improved from their initial Frankel grade compared to only 24% of reference patients (Frankel scale ranges from grade A, representing complete injury, to grade E, normal function). In addition, eight protocol but no reference patients improved from complete motor quadriplegia to independent ambulation. Finally, the protocol patients needed less intensive-care and hospital time.

Using a meta-analysis approach, a number of recent review articles have attempted to provide a big-picture assessment of the many decompression studies published over the years, including 1) The Role and Timing of Decompression in Acute Spinal Cord Injury (Fehlings MG et al, Spine 26(24S), 2001); 2) The Timing of Surgical Intervention in the Treatment of Spinal Cord Injury: A Systematic Review of Recent Clinical Evidence (Fehlings MG & Perrin RG, Spine 31(11S), 2006), and 3) Does Early Decompression Improve Neurological Outcome of Spinal Cord Injured Patients? (La Rosa G et al, Spinal Cord, 42(9), 2004.).

Although these articles do not provide a thumbs-up or -down recommendation for the use of decompression surgery in acute SCI, cumulative evidence suggests that the procedure 1) does not increase the complication rate after acute SCI, as suggested in earlier studies, 2) provides benefit for certain types of injuries, and 3) reduces the time spent in intensive care. Because definite data indicating its superiority over conservative-management approaches are lacking, the procedure should be considered a valid practice option but not a standard of care.

Chronic Injury

As reviewed by Dr. Wise Young (New Jersey, USA), some studies suggest that delayed surgical decompression, even long after the acute injury phase, can produce some restored function.

The potential beneficial influence of such decompression is, however, a confounding factor in interpreting the results of new function-restoring SCI therapies that are emerging throughout the world. Specifically, if the supposed function-restoring intervention (e.g., cell transplantation) is structurally affecting the cord’s injury site, it may be relieving some of the compression caused by the injury. As such, it may be difficult to attribute any regained function to the intervention alone; it may be just a consequence of the decompression and the ensuing enhanced flow of blood and cerebrospinal fluid.

Dr. Henry Bohlman (photo) and colleagues (Ohio, USA) have published a number of studies suggesting that decompression may be beneficial for patients with SCI who are beyond the acute phase of injury.

One of their studies focused on patients with incomplete, cervical injuries (J Bone Joint Surg Am, 74(5), 1992). In these patients, myelography (a form of x-ray examination using an injected dye) was used to determine whether bone or vertebral disk fragments were compressing the spinal cord’s anterior side. If so demonstrated, the compression was alleviated through anterior-decompression surgery followed by stabilization using iliac (i.e., hip) bone grafts. The time between injury and decompression averaged 13 months (range, one month to nine years), and patients were followed on average six years (range, 2-17 years). Of the 55 followed patients, 29 became functional walkers, and 39 recovered additional upper-extremity function. Only nine regained no motor function. In general, the more time that had elapsed since injury, less improvement accrued.

A similar study focused on patients with complete quadriplegia (J Bone Joint Surg Am, 74(5), 1992). In this study, the injury-to-decompression time averaged 15 months (range, one month to eight years), and patients were followed on average five years (range, 2-13 years). Of the 46 followed patients, seven improved at least two functional levels, and 18 improved one level. No motor improvement was note in 20 patients. Once again, more benefits were obtained by patients who were decompressed sooner after injury.