Failure of reduction with the aforementioned nonoperative maneuvers requires sur- gical reduction. Although a posterior approach has traditionally been advocated,22 anterior approaches are effective and may even be preferred, because any herniated disk fragments can be removed.20,23 Intraoperative reduction can be obtained ante- riorly with the use of distraction, applied either through distraction posts or with a laminar spreader (Tips from the Masters 14-5).20,24 This procedure is monitored by fluoroscopy and by measurement of spinal evoked potentials to decrease the risk of neurologic deterioration.
Tips from the Masters 14-5 • Expandable cages can be used to help provide further distraction to release locked facets.
Once reduction has been obtained, complete decompression and interbody fusion is performed. Fixation is achieved using an anterior cervical plate. In most cases this is sufficient, and combined anterior-posterior techniques are not needed.
Open reduction through a posterior approach can usually be achieved by manual manipulation of the spinous processes, with flexion moments applied initially to unlock the joints and then compression to fully reduce kyphosis. A curette or eleva- tor can be placed into the joint to act as a lever to elevate and reduce the dislocated vertebra. Difficult cases may require the removal of a small amount of the overriding facet with a bur to aid in reduction. After reduction a posterior fusion using lateral mass screws is performed. In some patients with extensive lateral mass comminu- tion that precludes secure screw placement across the involved segments, additional levels may need to be incorporated into the fusion.
DISCUSSION OF BEST EVIDENCE
The goal of treatment of any incomplete spinal cord injury is the prevention of fur- ther injury and the optimization of the chances for neurologic recovery (Figure 14-7).
Rapid decompression of neural elements is paramount in accomplishing these goals and is supported not only by empiricism, but also by animal and Level III clinical studies. Several animal studies have demonstrated that the severity and permanence of spinal cord injury is directly related to the duration and magnitude of compres- sion.2,3,6,25 Carlson and colleagues4 demonstrated in an animal model that a critical time period of 1 to 3 hours may exist beyond which neurologic recovery may not be possible in the setting of ongoing compression. These results are consistent with those of Delamarter and associates, who showed recoverability of function when neurologic
compression was relieved within 1 hour and no recoverability after 6 or more hours of compression.5
Clinical evidence supporting early cord decompression is composed of case reports and series. Several large retrospective studies have reported on the safe and effective use of closed reduction in cervical facet fracture dislocations. Hadley and co-workers12 reported on the treatment of 68 patients with facet fracture dislo- cation, with closed reduction attempted on 66. Although reduction was successful in only 58% of patients, neurologic improvement was seen in 78%, and it appeared that the timing of the reduction, whether by open or closed means, was the most important factor influencing recovery. Grant and associates11 reported a 97.6%
success rate in reduction in their series of 82 patients with cervical subluxations secondary to facet dislocations or other fractures. Postreduction MRI revealed disk herniation in 22% of patients and disk space disruption in 24%, although these findings had no effect on outcome. Lee and colleagues reported on a series of 210 patients, of whom 91 were treated by manipulation under anesthesia and 119 were treated by rapid traction.13 They reported a greater success rate with rapid traction (88% vs. 73%) as well as greater safety, with six patients experiencing declining neurologic function with reduction under anesthesia versus one with rapid traction. Several other series have corroborated the safety and efficacy of closed reduction.26-28
Closed reduction of cervical facet dislocations with traction is not without risk.
The most feared complication is neurologic deterioration, thought to be most often
Dislocated Facets
ASIA A-C ASIA D-E
MRI No Yes
Disk herniation No disk
herniation
Disk herniation No disk
herniation
No
Yes
Contraindications to traction:
-Rostral injury -Skull fracture
underlying pin site
Emergent closed reduction
Emergent surgical reduction and stabilization
Successful reduction AND stable exam?
Anterior decompression and stabilization
Anterior or posterior stabilization
Immobilize spine:
-Urgent MRI
Anterior surgical reduction and fixation
Closed reduction followed by surgical stabilization
FIGURE 14-7 Treatment algorithm for dislocated facets. ASIA, American Spinal Injury Association Impair- ment Scale.
secondary to disk herniation. Two case reports have described neurologic deterio- ration from herniation and have caused physicians much pause in instituting trac- tion, with some arguing for prereduction MRI in all patients.16,17 This well-publicized risk has led to several investigations of disk herniations and traction. In a prospec- tive study, Vaccaro and colleagues18 obtained prereduction and postreduction MRI scans for 11 patients with cervical dislocations. Among the nine patients undergoing success reductions, disk herniations were found in two before reduction and in five after reduction. No patient, however, experienced a neurologic worsening. Darsaut and associates reported on the use of MRI guidance in the reduction of cervical dislocations and observed an increase in spinal canal diameter in 11 of 17 patients undergoing traction, with herniated disk material being pulled back toward the disk space.15
The usefulness of MRI before traction in patients with incomplete neurologic deficit is thus debatable. In patients with incomplete neurologic injuries, a delay in treatment while MRI is performed can theoretically lead to an exacerbation of injury or the conversion of a reversible injury into an irreversible one, because the duration of neurologic compression is inversely related to the probability of recovery in ani- mal models, as discussed earlier. Furthermore, exactly what findings on an MRI scan would preclude the application of traction is unclear, because traction has certainly been applied without adverse effect in the setting of disk disruption and herniation.
MRI remains an option in patients with incomplete neurologic injury if it is read- ily available and will not substantially delay reduction. MRI can be more strongly considered in patients who are unexaminable due to a head injury, intoxication, or other causes, because in such cases a neurologic decline will not be detectable if it should occur during the application of traction. If a herniated disk fragment is detected, thought should be given to operative decompression and reduction at the earliest possible time.
The application of traction can also cause neurologic decline through overdistrac- tion, which can occur with the use of too much weight or the failure to recognize a more rostral lesion.22,29-33 A missed atlantooccipital dislocation is a well-reported and serious cause of deterioration when traction is used, and the patient must be carefully screened for such a dislocation before application of traction.22,34 In total, the risk of permanent neurologic deterioration from closed reduction appears to be less than 1.0%16,26,27,35,36; transient neurologic deficits occur with a slightly higher frequency (2% to 4%) and are mostly reversible with reduction of traction.26,37 Moreover, no permanent neurologic injury has been described in an awake and examinable patient undergoing closed reduction of a cervical facet dislocation. This underscores the importance of the examination of the patient when traction is used, and for this reason reduction in the awake, examinable patient may actually be safer than reduction under general anesthesia at the time of operation.
Surgical reduction of cervical jumped facets is performed when traction is unsuc- cessful and can be accomplished using either an anterior or posterior approach.38 Advantages of a posterior approach include the ability to obtain reduction of jumped facets directly and the greater biomechanical strength of posterior stabilization con- structs compared with anterior constructs.39 Anterior approaches, on the other hand, enable the direct removal of herniated disk material and allow the dislocation to be stabilized with the fusion of only the involved levels, whereas the posterior approach may necessitate instrumentation of additional levels, especially if significant amounts of facet are removed to accomplish reduction. Although anterior constructs are not as robust biomechanically as posterior constructs, fusion rates of more than 90% are reported, and outcomes for the two techniques are similar.38,40,41 Combined anterior and posterior approaches may be preferred by some, but circumferential stabiliza- tion is usually not necessary.
In summary, the best animal and clinical human evidence indicates that there is an advantage to early decompression of the spinal cord in cases of spinal cord injury. In the case of jumped cervical facets decompression can be accomplished most rapidly in a closed fashion, with the use of cranial tongs and traction. In an awake, examinable patient, such reduction should be carried out as soon as
possible. In cases in which closed reduction is not possible, early open reduction from an anterior or posterior approach is indicated.
COMMENTARY
Closed traction of facet dislocations in patients with neurologic injuries is the most expeditious means to improve local spinal cord flow and reduce secondary effects of spinal cord injury and compression. Anecdotal case reports have shown that rapid reduction within 1 to 2 hours may reverse quadriplegia. Delaying reduction to perform imaging such as MRI or to prepare for surgery may increase the duration of neural compression, exceeding the small window of opportunity to obtain the benefits of immediate reduction.
Closed reduction with tong traction is safe and effective in realigning the spine in the majority of patients. Contraindications include skull fractures and unstable inju- ries rostral to the cervical dislocation, including atlantooccipital dislocations, odon- toid fractures, and hangman’s fractures. Ankylosing spondylitis represents a relative contraindication to traction. Large retrospective case series of closed reduction via cranial tongs in awake patients have shown that neurologic worsening occurs in 1%
to 2% of cases. This is usually transient and is secondary to overdistraction. Reduc- tion of all fracture types is achieved in 75% to 95% of cases, although large traction weights may be required. Once reduction is achieved, traction weights can generally be reduced and definitive treatment performed.
REFERENCES
1. Sonntag VK: Management of bilateral locked facets of the cervical spine, Neurosurgery 8(2):150–152, 1981.
2. Tarlov IM, Klinger H: Spinal cord compression studies. II. Time limits for recovery after acute com- pression in dogs, AMA Arch Neurol Psychiatry 71(3):271–290, 1954.
3. Dolan EJ, Tator CH, Endrenyi L: The value of decompression for acute experimental spinal cord compression injury, J Neurosurg 53(6):749–755, 1980.
4. Carlson GD, Minato Y, Okada A, et al: Early time-dependent decompression for spinal cord injury:
vascular mechanisms of recovery, J Neurotrauma 14(12):951–962, 1997.
5. Delamarter RB, Sherman J, Carr JB: Pathophysiology of spinal cord injury. Recovery after immediate and delayed decompression, J Bone Joint Surg Am 77(7):1042–1049, 1995. Delamarter and colleagues demonstrate the critical correlation between time of neurologic compression and histologic neuro- logic damage, and electrophysiologic and clinical recovery. Their results are consistent with those of other animal and human studies indicating that prolonged neurologic compression leads to greater injury. Conversely, timely decompression allows improved recovery.
6. Tarlov IM: Spinal cord compression studies. III. Time limits for recovery after gradual compression in dogs, AMA Arch Neurol Psychiatry 71(5):588–597, 1954.
7. Cowan JA Jr, McGillicuddy JE: Images in clinical medicine. Reversal of traumatic quadriplegia after closed reduction, N Engl J Med 359(20):2154, 2008.
8. Brunette DD, Rockswold GL: Neurologic recovery following rapid spinal realignment for complete cervical spinal cord injury, J Trauma 27(4):445–447, 1987.
9. Wolf A, Levi L, Mirvis S, et al: Operative management of bilateral facet dislocation, J Neurosurg 75(6):883–890, 1991.
10. Cotler JM, Herbison GJ, Nasuti JF, et al: Closed reduction of traumatic cervical spine dislocation using traction weights up to 140 pounds, Spine 18(3):386–390, 1993.
11. Grant GA, Mirza SK, Chapman JR, et al: Risk of early closed reduction in cervical spine sublux- ation injuries, J Neurosurg 90(Suppl 1):13–18, 1999. Grant and colleagues report on a large retro- spective study of the utility of closed reduction in treatment of cervical spine injuries. Ninety-seven percent of 82 patients underwent successful reduction using closed methods. Although 22% of patients had postreduction disk herniation evident on MRI scans, this was not found be clinically significant.
12. Hadley MN, Fitzpatrick BC, Sonntag VK, et al: Facet fracture-dislocation injuries of the cervical spine, Neurosurgery 30(5):661–666, 1992. Hadley and colleagues reported on the use of closed and open reduction techniques in a series of 68 patients with cervical facet fracture-dislocation injuries.
Although closed techniques were successful only 58% of the time in this study, the timing of reduction by any method was the strongest variable correlating with neurologic outcome.
13. Lee AS, MacLean JC, Newton DA: Rapid traction for reduction of cervical spine dislocations, J Bone Joint Surg Br 76(3):352–356, 1994.
14. Rizzolo SJ, Vaccaro AR, Cotler JM: Cervical spine trauma, Spine 19(20):2288–2298, 1994.
15. Darsaut TE, Ashforth R, Bhargava R, et al: A pilot study of magnetic resonance imaging–guided closed reduction of cervical spine fractures, Spine 31(18):2085–2090, 2006.
16. Farmer J, Vaccaro A, Albert TJ, et al: Neurologic deterioration after cervical spinal cord injury, J Spinal Disord 11(3):192–196, 1998.
17. Maiman DJ, Barolat G, Larson SJ: Management of bilateral locked facets of the cervical spine, Neurosurgery 18(5):542–547, 1986.
18. Vaccaro AR, Falatyn SP, Flanders AE, et al: Magnetic resonance evaluation of the intervertebral disc, spinal ligaments, and spinal cord before and after closed traction reduction of cervical spine disloca- tions, Spine 24(12):1210–1217, 1999. Vaccaro and colleagues obtained prereduction and postreduction MRI scans for 11 patients with cervical spine dislocations and noted an increase in the incidence of disk herniations after reduction. No neurologic deficits were attributed to this finding. These results should alert clinicians to disk herniation as a potential cause of neurologic decline after closed reduc- tion, and this possibility should be examined.
19. Blumberg KD, Catalano JB, Cotler JM, et al: The pullout strength of titanium alloy MRI-compatible and stainless steel MRI-incompatible Gardner-Wells tongs, Spine 18(13):1895–1896, 1993.
20. Vital JM, Gille O, Sénégas J, et al: Reduction technique for uni- and biarticular dislocations of the lower cervical spine, Spine 23(8):949–954; discussion, 955, 1998.
21. Lu K, Lee TC, Chen HJ: Closed reduction of bilateral locked facets of the cervical spine under general anaesthesia, Acta Neurochir (Wien) 140(10):1055–1061, 1998.
22. Bohlman HH: Acute fractures and dislocations of the cervical spine. An analysis of three hundred hospitalized patients and review of the literature, J Bone Joint Surg Am 61(8):1119–1142, 1979.
23. de Oliveira JC: Anterior reduction of interlocking facets in the lower cervical spine, Spine 4(3):
195–202, 1979.
24. Fazl M, Pirouzmand F: Intraoperative reduction of locked facets in the cervical spine by use of a modi- fied interlaminar spreader: technical note, Neurosurgery 48(2):444–445; discussion, 445-446, 2001.
25. Jelsma RK, Rice JF, Jelsma LF, et al: The demonstration and significance of neural compression after spinal injury, Surg Neurol 18(2):79–92, 1982.
26. Initial closed reduction of cervical spine fracture-dislocation injuries, Neurosurgery 50(Suppl 3):
S44–S50, 2002.
27. Mahale YJ, Silver JR, Henderson NJ: Neurological complications of the reduction of cervical spine dislocations, J Bone Joint Surg Br 75(3):403–409, 1993.
28. Star AM, Jones AA, Cotler JM, et al: Immediate closed reduction of cervical spine dislocations using traction, Spine 15(10):1068–1072, 1990.
29. Scher AT: Overdistraction of cervical spinal injuries? S Afr Med J 59(18):639–641, 1981.
30. Gruenberg MF, Rechtine GR, Chrin AM, et al: Overdistraction of cervical spine injuries with the use of skull traction: a report of two cases, J Trauma 42(6):1152–1156, 1997.
31. Key A: Cervical spine dislocations with unilateral facet interlocking, Paraplegia 13(3):208–215, 1975.
32. Schaefer DM, Flanders A, Northrup BE, et al: Magnetic resonance imaging of acute cervical spine trauma. Correlation with severity of neurologic injury, Spine 14(10):1090–1095, 1989.
33. Fried LC: Cervical spinal cord injury during skeletal traction, JAMA 229(2):181–183, 1974.
34. Guigui P, Milaire M, Morvan G, et al: Traumatic atlantooccipital dislocation with survival: case report and review of the literature, Eur Spine J 4(4):242–247, 1995.
35. Fehlings MG, Tator CH: An evidence-based review of decompressive surgery in acute spinal cord injury: rationale, indications, and timing based on experimental and clinical studies, J Neurosurg 91 (Suppl 1):1–11, 1999.
36. Mahale YJ, Silver JR: Progressive paralysis after bilateral facet dislocation of the cervical spine, J Bone Joint Surg Br 74(2):219–223, 1992.
37. Wimberley DW, Vaccaro AR, Goyal N, et al: Acute quadriplegia following closed traction reduction of a cervical facet dislocation in the setting of ossification of the posterior longitudinal ligament: case report, Spine 30(15):E433–E438, 2005.
38. Brodke DS, Anderson PA, Newell DW, et al: Comparison of anterior and posterior approaches in cervical spinal cord injuries, J Spinal Disord Tech 16(3):229–235, 2003.
39. Coe JD, Warden KE, Sutterlin CE 3rd, et al: Biomechanical evaluation of cervical spinal stabilization methods in a human cadaveric model, Spine 14(10):1122–1131, 1989.
40. Garvey TA, Eismont FJ, Roberti LJ: Anterior decompression, structural bone grafting, and Caspar plate stabilization for unstable cervical spine fractures and/or dislocations, Spine 17(Suppl 10):S431–S435, 1992.
41. Johnson MG, Fisher CG, Boyd M, et al: The radiographic failure of single segment anterior cervical plate fixation in traumatic cervical flexion distraction injuries, Spine 29(24):2815–2820, 2004.
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