Distraction extension injuries of the cervical spine.

Twenty-four consecutive patients with cervical distraction extension injuries were retrospectively reviewed to study the safety and efficacy of various treatment protocols in this type of cervical spine injury. Sixteen of 24 patients with cervical distraction extension injuries underwent surgical stabilization. All patients undergoing surgical stabilization were noted to have a stable fusion at their latest follow-up. There were three instances of surgically related neurologic deterioration as a result of over-distraction of the anterior column interspace at the time of graft placement. The overall mortality rate was 42% in this aged patient population. Anterior reconstruction of the cervical spine with an anterior cervical graft and plate acting as a tension band is the ideal treatment method for stabilization of acute distraction extension injuries involving primarily the soft tissue structures (anterior longitudinal ligament and intervertebral disc). Type 2 injuries, depending on the degree of displacement and the adequacy of closed reduction, may need to be approached initially posteriorly to obtain adequate alignment, followed by an anterior reconstructive procedure. Great care should be taken during anterior graft placement to avoid over-distraction of the spine. If nonsurgical intervention is selected, close regular radiographic follow-up is necessary to detect early vertebral malalignment, which may predispose to spinal cord dysfunction. Older patients sustaining this injury have a high mortality rate.

The significance of thoracolumbar spinal canal size in spinal cord injury patients.

STUDY DESIGN: A prospective, consecutive case series. OBJECTIVES: To determine the relation between spinal canal dimensions and Injury Severity Score and their association with neurologic sequelae after thoracolumbar junction burst fracture. SUMMARY OF BACKGROUND DATA: There is a relation in the cervical spine between spinal canal dimension and its association with neurologic sequelae after trauma. A similar relation at the thoracolumbar junction has not been conclusively established. METHODS: Forty-three patients with thoracolumbar junction burst fractures (T12-L2),13 with and 30 without neurologic deficit, were included. Computed tomographic scans were used to measure the sagittal and transverse diameters and the surface area of the spinal canal at the level of injury, as well as one level above and one level below the fracture level. Injury severity score was calculated for both groups. Statistical analysis comparing those with a neurologic deficit to those without was performed by Student's t test. RESULTS: The ratio of sagittal-to-transverse diameter at the level of injury was significantly smaller in patients with a neurologic deficit than in those without a neurologic deficit (P < 0.05). The mean transverse diameter at the level of injury was significantly larger in patients with neurologic deficit than in the neurologically intact patients (P < 0.05). The surface area of the canal at the level below the injury was significantly larger in the patients with a neurologic deficit than in those without a deficit (P < 0.05). Patients with a neurologic deficit had a statistically higher Injury Severity Score when admitted than those without a neurologic deficit (P < 0.0001), although the difference became insignificant after the neurologic component of the scoring system was eliminated. CONCLUSION: There are no anatomic factors at the thoracolumbar junction that predispose to neurologic injury after burst fracture. The shape of the canal after injury, however, as determined by the sagittal-to-transverse diameter ratio, was predictive of neurologic deficit.

Health outcome assessment before and after anterior cervical discectomy and fusion for radiculopathy: a prospective analysis.

STUDY DESIGN: A prospective assessment, performed using the Health Status Questionnaire, of the outcomes for 28 patients with cervical radiculopathy treated with one- or two-level anterior cervical discectomy and fusion. OBJECTIVE: To assess patient outcome using the Health Status Questionnaire after one- or two-level anterior cervical discectomy and fusion. SUMMARY OF BACKGROUND DATA: Although outcomes for many types of surgical procedures already have been evaluated, few have focused on the results of cervical surgery. METHODS: Before and after anterior cervical discectomy and fusion for cervical radiculopathy, 28 patients filled out the Health Status Questionnaire. The average follow-up interval was 21.8 months. There were 10 men and 18 women, with an average age of 44 years. All outcome instruments were graded for individual scores of general health, physical function, role limitation because of physical health problems, role limitation because of emotional problems, social function, mental health, bodily pain, and energy. Data were analyzed using the age (< 55 vs. > 55), worker's compensation status, and education status of the patient. Preoperative and postoperative scores were compared for each subscale. RESULTS: Statistically significant improvements were found in postoperative scores for bodily pain (P < 0.001), vitality (P = 0.003), physical function (P = 0.01), role function/physical (P = 0.0003), and social function (P = 0.0004). No significant differences were found before and after surgery for three health scales: general health, mental health, and role function associated with emotional limitations. Age, educational status, and history of compensation litigation did not appear to affect outcome measures. CONCLUSIONS: Although this is a preliminary report involving 28 patients, it would appear, based on the results of the Health Status Questionnaire, that anterior cervical discectomy and fusion performed on appropriately selected patients is a highly reliable surgical procedure for the management of cervical radiculopathy. Additional disease-specific questions may provide more sensitivity in evaluating radiculopathy after surgical and nonsurgical intervention.

The efficacy of using an image-guided Kerrison punch in performing an anterior cervical foraminotomy. An anatomic analysis.

STUDY DESIGN: This study comprised two parts: first, a feasibility study to determine the efficacy of using an image-guided Kerrison punch while performing a foraminotomy during an anterior cervical decompression and, second, an anatomic analysis using vector measurement to determine the distance from the entrance of the neuroforamen to the medial margin of the vertebral artery in the subaxial cervical spine. OBJECTIVE: To assess the feasibility of using an image-guided Kerrison punch when performing an anterior foraminotomy and to obtain data regarding the distance from the vertebral artery to the entrance of the neuroforamen. SUMMARY OF BACKGROUND DATA: The documented incidence of catastrophic iatrogenic vertebral artery injury in anterior cervical decompression is low. The use of a real-time image-guidance surgical system should reduce the risk of this complication. METHODS: Twelve cadaveric cervical spines were harvested. Standard anterior cervical discectomies with bilateral foraminotomies were performed in the subaxial cervical spine using an image-guided Kerrison. Surgically significant morphometric data were measured using a computer-assisted image-guided surgical system. RESULTS: Successful navigation into all neuroforamina in the subaxial cervical spine was attained using the image-guided Kerrison punch. The vector measurement from the neuroforamen to the vertebral artery averaged 5.8 +/- 1.2 mm at C3-C4, 6.5 +/- 1.6 mm at C4-C5, 7.9 +/- 1.4 mm at C5-C6, and 9.1 +/- 1.8 mm at C6-C7. Statistically significant differences (P < 0.05) were found between all cervical levels except C3-C4 and C4-C5. CONCLUSION: An image-guided Kerrison punch may be used successfully when performing cervical foraminotomies during an anterior cervical discectomy, thus eliminating the risk of potential vertebral artery injury. These data confirm previous findings by other authors. Knowledge of these data may aid the spine surgeon in performing a foraminotomy during anterior cervical decompression.

Efficacy of magnetic resonance imaging in the evaluation of posterior cervical spine fractures.

STUDY DESIGN: A retrospective study using two independent, blinded musculoskeletal radiologists to evaluate the sensitivity, specificity, and predictive value of cervical spine magnetic resonance imaging in detecting posterior element fractures of the cervical spine. OBJECTIVE: To evaluate the sensitivity, specificity, and predictive value of magnetic resonance imaging, using computed tomographic scanning as the gold standard, in the diagnosis of posterior element cervical spine fractures. SUMMARY OF BACKGROUND DATA: Few investigators have evaluated the accuracy of magnetic resonance imaging in the determination of cervical spine fractures. METHODS: From January 1994 through June 1996, 75 cervical spine fractures in 32 patients were confirmed by computed tomography. Two musculoskeletal radiologists who were blinded to the clinical history and presence or absence of cervical injury among the study population, independently evaluated each cervical magnetic resonance image recording the presence or absence of soft tissue or bony injury. RESULTS: The overall sensitivity and specificity rates for the diagnosis of a posterior element fracture by magnetic resonance imaging was 11.5% and 97.0%, respectively. The positive predictive value for this group was 83%, and the negative predictive value was 46%. In reference to anterior fractures, the sensitivity was 36.7% and the specificity 98%. Positive and negative predictive values were 91.2% and 64%, respectively. CONCLUSIONS: Magnetic resonance imaging was not effective in recognizing bony injury to the cervical spine and in particular was not as sensitive or as specific as computed tomography in identifying cervical spinal fractures. Computed tomography remains the study of choice for the detection and precise classification of bony injuries to the cervical region, especially when plain radiographs are difficult to evaluate. Magnetic resonance imaging, although not as effective as computed tomography in defining specific bony disorders, remains the gold standard in the evaluation of spinal cord injury, occult vascular injury, and intervertebral disc disruption (hyperextension injury), including herniation and other soft tissue disorders (hematoma, ligament tear).

Image-guided anterior cervical corpectomy. A feasibility study.

STUDY DESIGN: A feasibility study was performed to determine the efficacy of using image-guided frameless stereotaxy to perform anterior corpectomy of the cervical spine. OBJECTIVE: To assess the feasibility of using image-guided stereotaxy in performing anterior cervical corpectomy. SUMMARY OF BACKGROUND DATA: Anterior cervical decompression including discectomy and corpectomy is a commonly performed procedure. Particular concern about invasion of the vertebral artery arises while performing this procedure to gain maximal lateral decompression. At present, surgeons have only landmarks and experience to guide them in performance of this potentially dangerous procedure. METHODS: Four cadavers (average age, 40.3 years) were used. A lateral corpectomy trough was created in Group 1 by a standard technique using visual landmarks. In the second group of corpectomy troughs, an image-guided frameless stereotactic system was used. After completion of the experiment, each cadaver had a corpectomy trough at every level on one side performed in a standard manner and on the other with image guidance. Using the image guidance system, an independent observer measured the distance from the corpectomy trough (lateral border) to the medial border of the foramen transversarium. RESULTS: The average distance from the lateral border of the trough to the medial border of the foramen transversarium in the standard trough group was 5.10 mm (range, 1.72-7.71 mm), and the average distance from the medial border of the foramen transversarium to the image-guided trough was 4.34 mm (range, 3.34-5.48 mm). The trend of the comparison between the two troughs was toward significance at P = 0.08. CONCLUSIONS: Image-guidance provided improved accuracy when compared with that of a standard technique, implying clinical potential for image-guided corpectomy. Less variability is seen using an image-guided approach.

Bilateral peroneal nerve palsy secondary to a knee board: report of two cases.

We report on two patients who developed bilateral peroneal nerve palsy after using a knee board behind a water ski boat. This device causes the rider's knees to be in a hyperflexed position secured with a strap across the thighs. Treatment for this compressive neuropathy is conservative. Recreational users may wish to limit the duration and frequency of participation in this sport, thus decreasing the predisposition to prolonged nerve compression. In addition, manufacturers may consider making fundamental design changes such as padding the nylon straps or outrigger devices that contact the proximal lateral tibia.

Use of cervicothoracic junction pedicle screws for reconstruction of complex cervical spine pathology.

STUDY DESIGN: A retrospective review of 21 patients in which cervical pedicle screw fixation was used at C7 with or without upper thoracic pedicle screw fixation. OBJECTIVE: To evaluate the use of pedicle screw placement in the lower cervical spine. SUMMARY OF BACKGROUND DATA: The use of posterior cervical spine fixation, including lateral mass fixation, has become increasingly popular in recent years. However, lateral mass fixation at C7 is often hindered by lack of substantial high quality bone. The end level of long cervical spine constructs is frequently C7 or T1. Dissatisfaction with lateral mass fixation at C7 and T1 led the authors to use lower cervical pedicle screw fixation for several cervical spine disorders. METHODS: Twenty-one patients who had undergone cervical pedicle screw fixation at C7 were reviewed retrospectively. There were 12 males and 9 females, with an average age of 52 years. All pedicle screws were placed, after direct palpation of the pedicle, with a right angle nerve hook after laminoforaminotomy at C7. RESULTS: There were no neurologic complications related to pedicle screw placement, and no patient was symptomatically worse after the operation. Six patients with root pathology improved. Of 14 patients with cervical myelopathy, 12 improved at least one Nurick grade, and 2 had no improvement. There were no failures of fixation or complications related to pedicle fixation at a minimum of 1 year follow-up. CONCLUSION: Pedicle screws in C7 placed with laminoforaminotomy and palpation technique appears to be safe and efficacious. Excellent fixation can be achieved.

Long-term evaluation of vertebral artery injuries following cervical spine trauma using magnetic resonance angiography.

STUDY DESIGN: A prospective study to determine the long-term outcome of traumatically induced vertebral artery injuries. Magnetic resonance angiography was performed at the time of cervical injury and at a follow-up office visit. OBJECTIVE: To determine the long-term outcome in terms of arterial flow competency of traumatically induced vertebral artery injuries. SUMMARY OF BACKGROUND DATA: Vertebral artery injury associated with cervical spine trauma has been well documented; however its healing or nonhealing potential has not been elucidated. METHODS: During the 7-month period from July 1993 to January 1994, all patients admitted to the authors' institution with cervical spine injuries underwent magnetic resonance imaging and magnetic resonance angiography of the cervical spine to determine the patency of their vertebral arteries. Magnetic resonance angiography was performed at the time of injury and at a follow-up office visit. Twelve of 61 patients were found to have a lack of signal flow within one of their vertebral vessels during this study period. RESULTS: Eighty-three percent of the patients (five of six) who were available for follow-up observation in this study did not manifest flow reconstitution of their vertebral arteries after an average 25.8-month follow-up period. CONCLUSIONS: According to these data, most patients with vertebral artery injuries after nonpenetrating cervical spine trauma do not reconstitute flow in the injured vertebral arteries. This lack of flow must be considered if future surgery in this region of the cervical spine is contemplated.

The benefits of early decompression in cervical spinal cord injury.

Decompression and stabilization have been shown to improve neurologic outcome in cases of cervical spine trauma with proven compression of the spinal cord. This paper reviews experimental and clinical research to clarify the benefits of early surgery for cervical spinal cord injury. The direct clinical benefit of early surgery is a theoretic improvement in neurologic recovery over that of delayed surgery. Additional benefits of early surgery include the clinical advantages of a decreased length of hospitalization and its associated complications and a decreased time to rehabilitation and mobilization. Proper, timely surgical intervention can better the physiologic environment so as to allow for maximum neurologic improvement.