Thirty-six years experience of cervical extension osteotomy in ankylosing spondylitis: techniques and outcomes

STUDY DESIGN

A retrospective review of the cervical extension osteotomy in the past 36 years for the treatment of flexion deformity of patients with ankylosing spondylitis was conducted.

OBJECTIVES

To review the conventional and current surgical techniques of cervical extension osteotomy in ankylosing spondylitis and to evaluate the clinical outcomes.

SUMMARY OF BACKGROUND DATA

Cervical osteotomy is a challenging procedure in the correction of flexion deformity in ankylosing spondylitis. Some authors prefer using general anesthesia and prone position for their surgery, and some, including the authors, use the sitting position.

METHODS

A review of 131 cases of cervical spine osteotomy was carried out. The accumulation of 131 cases was classified into two phases: 114 cases from 1967 to 1997 (conventional technique group) by our senior author and 17 cases from 1997 to 2003 (current technique group) by our first author. Patient follow-up was obtained by a combination of retrospective chart review and telephone interview by 2 independent physicians. The flexion deformity was measured before surgery and after surgery using chin-brow to vertical angle.

RESULTS

There were 114 patients in the conventional group and 17 patients in the current group. The average preoperative and postoperative angle was 56 degrees and 4 degrees , respectively, in the conventional group and 49 degrees and 12 degrees , respectively, in the current group.

CONCLUSIONS

The sitting position with local anesthesia is safe and allows for correction of deformity in a controlled manner. The increased lateral resection area reduces the possibility of nerve root impingement and provides ample room for the spinal cord. The cranial halo can also be adjusted after surgery to modify the head/neck position and can be adjusted to alleviate any C8 nerve root impingement. The procedure demands great attention to detail to minimize risk.

Vertebral tumors: surgical versus nonsurgical treatment

The treatment of spinal tumors represents a challenge to spine care professionals. Fortunately, the incidence of new cases of primary malignant bone tumors is lower compared with that of other tumors. In the United States approximately 2000 malignant bone tumors of 7000 new sarcomas are diagnosed each year. Of these, 4% to 20% (80-400 tumors) of bone tumors are spinal tumors. Metastatic tumors are the most frequent tumor of bone and the most frequent tumor of the spinal column regardless of the origin of the primary tumor. More than 90% of spinal tumors are metastatic. Thirty to seventy percent of patients who die from cancer have evidence of vertebral metastases visible on careful postmortem examination, with the potential that this number could reach 85% in patients with breast cancer. Less than 10% of patients with spinal tumors present with spinal instability requiring surgical treatment; this accounts for approximately 18,000 new cases yearly. We will focus on the most recent advances in nonsurgical and surgical treatment of vertebral tumors. In surgical treatment, the evaluation and selection of patients, indications and surgical strategies, open and minimally invasive techniques, outcomes and complications will be discussed.

LEVEL OF EVIDENCE

Level V (expert opinion). See the Guidelines for Authors for a complete description of the levels of evidence.

Value of magnetic resonance imaging and discography in determining the level of cervical discectomy and fusion

STUDY DESIGN

The correlation between magnetic resonance imaging and discography of the cervical spine in degenerative disc disease was studied. In addition, the results of cervical discectomy and fusion were evaluated.

OBJECTIVES

To compare the value of cervical magnetic resonance imaging versus discography in selecting the level for discectomy and fusion and to evaluate the surgical outcome.

SUMMARY OF BACKGROUND DATA

The value of magnetic resonance imaging and discography in patients with cervical discogenic pain is less clear. Also, the status of a hypointense signal (dark) cervical disc and/or a small herniated disc on magnetic resonance imaging has not been determined.

METHODS

The magnetic resonance imaging studies and discography followed by computed tomography in 55 patients with cervical discogenic pain were evaluated. Surgical planning was based on the complete information of clinical symptoms, magnetic resonance imaging, and discography as well as computed tomography discography. Anterior cervical discectomy and keystone fusion was performed. Postoperative pain relief was assessed by the patients, and the follow-up radiographs were viewed by an independent reviewer. The overall surgical outcome was evaluated using Odom's criteria.

RESULTS

There were 161 disc levels that successfully underwent cervical discography with 79 positive levels. A positive discography result was found in 63% of dark (hypointense signal) discs and 45% of speckled discs. Fifty-nine percent of small herniated discs and 59% of torn discs had a positive discography, respectively. There were 100 abnormal cervical discs on magnetic resonance imaging. Magnetic resonance imaging had a false-positive rate of 51% and a false-negative rate of 27%. Successful cervical fusion was achieved in 95% of patients, and the overall satisfactory result was 76%.

CONCLUSIONS

Magnetic resonance imaging can identify most of the painful discs but still has relatively high false-negative and false-positive rates. There is a high chance that hypointense signal and small herniated discs are the pain generators, but they are not always symptomatic. Discography can save the levels from being unnecessarily fused. The combination of clinical symptoms, magnetic resonance imaging, and discography provides the most information for decision making and can improve the management of cervical discogenic pain.

Active range of motion utilized in the cervical spine to perform daily functional tasks

This was a descriptive study to examine active range of motion required in the cervical spine during functional tasks of daily living. The objective of this study was to determine the mean active range of motion of the cervical spine required to perform 13 daily functional tasks. Previous research has examined the absolute ranges of cervical motion for women and men 20-60 years of age; however, no previous study has determined the amount and type of motion that is required for routine activities of daily living. Twenty-eight college-aged students (n = 28) served as healthy subjects and performed three trials of 13 daily tasks of functional activity. The subject's starting position and end range of motion for flexion-extension, rotation, and side bending of each task were observed and recorded using the cervical range of motion device. The three trials were averaged, and ranges of motion across the 28 subjects were reported. Of the 13 daily functional tasks performed, tying shoes (flexion-extension 66.7 degrees), backing up a car (rotation 67.6 degrees), washing hair in the shower (flexion-extension 42.9 degrees), and crossing the street (rotation head left 31.7 degrees and rotation head right 54.3 degrees) required the greatest full active range of motion of the cervical spine. Flexion-extension and rotation of the cervical spine are important to enable functional activity. Four of the 13 daily tasks performed required 30-50% of active range of motion. Side bending was seen to be coupled with rotation in completion of tasks. This article provides a baseline of normal motion of the neck required for activities of daily living and can be used in the assessment of disease states and disability.

Brown's procedure for congenital absence of the tibia revisited

The results of reconstructive surgery in tibial hemimelia using a modified fibular transfer procedure as described by Brown were reviewed. A modified Brown's procedure was carried out on five patients with a total of seven affected limbs. A Syme's-type amputation of the foot was carried out in each case. All of the knees had quadriceps function preoperatively, which was considered a prerequisite for surgery. Average length of follow-up was 7 years, with a range of 2-12 years. The average age at time of surgery was 12.7 months, with a range of 7-26 months. At the time of review, all patients had reasonably good function of their lower extremities. All were ambulating with patellar tendon-bearing prostheses and thigh extensions for collateral support. The average arc of motion at review was 57.4 degrees, with further passive motion possible in all cases. Average extension was -18.5 degrees, and the average active flexion was 76 degrees. We found that a fibular centralization procedure in a patient with at least grade III+ quadriceps function can give good functional results that do not appear to deteriorate over time.

Surgical treatment of patients with lumbar spinal stenosis with associated scoliosis

Spinal stenosis in combination with scoliosis frequently is seen in elderly patients. Patients typically present with a combination of symptoms attributable to neurogenic claudication and radicular pain, and symptoms of lower back pain. For patients in whom conservative treatment is not sufficient, surgical treatment can be done with careful consideration of the overall patient and his or her medical status. Surgical treatment is twofold; one purpose is to decompress the neural elements, the other purpose is to stabilize and realign the spine to as great a degree as possible. Appropriate balance of the spine at the end of the procedure is more important than the absolute amount of correction obtained. Stabilization and correction of the spine is done with pedicle screw-rod instrumentation and fusion, and the procedure must be done in an efficient and timely manner to involve the least amount of morbidity. There are two types of deformity typically seen, one is a degenerative lumbar scoliosis with no or minimal rotational deformity (Type I), and the other is a degenerative scoliosis often superimposed on a preexisting scoliosis with greater rotational deformity and greater loss of lordosis (Type II). Instrumentation and correction techniques differ for these two types of deformities, with shorter instrumentation procedures usually possible for the Type I deformity and longer instrumentation with sagittal plane reconstitution necessary for Type II deformity.

Thoracic and lumbar deformity: rationale for selecting the appropriate fusion technique (Anterior, posterior, and 360 degree)

The rationale of anterior versus posterior, or combined fusion is discussed with regards to different clinical diagnoses and situations. Factors involved in the decision-making process include stability, magnitude of deformity, rigidity of deformity, neurologic considerations, bone quality, and medical/metabolic factors. Careful preoperative assessment and planning are required as well as consideration for the patient's overall well being.

Cervical deformity: rationale for selecting the appropriate fusion technique (anterior, posterior, and 360 degree)

This article examines cervical deformities and their treatments, such as iatrogenic deformities, posttraumatic deformities, ankylosing spondylitis, rheumatoid arthritis, degenerative subaxial spondylolisthesis, myopathy, infectious spondylitis, and tumors. Congenital scoliosis and kyphosis and torticollis and rotatory atlanto-axial subluxation also are discussed.

Interobserver variability in grading lumbar fusions

Inter- and intraobserver variability in grading lumbar fusion status radiographically was assessed. The objective was to determine the interobserver variability and intraobserver reproducibility in the assessment of two level noninstrumented lumbar fusions. Fifty sets of radiographs with anteroposterior, left and right bending, and flexion-extension lateral views were assessed by six observers of varying experience and background, with fusion status graded. Kappa statistical analysis revealed only fair interobserver agreement in grading lumbar fusion status. Intraobserver reproducibility was higher in more experienced observers. The results indicate only fair reliability in terms of interobserver agreement to grading of lumbar fusion status. Variability in assessing lumbar fusion radiographically may explain some of the variability in fusion rates reported in the literature and poor correlation that can be seen between clinical outcome and radiologic outcome.

Reliability of roentgenogram evaluation of pedicle screw position

STUDY DESIGN

This was a human cadaver study of the accuracy of biplanar roentgenography in determining pedicle screw position.

OBJECTIVE

To determine the independent accuracy of radiologic evaluation of screw placement and to determine if there are any particular screw malpositions that are more likely to produce a false sense of acceptable screw position.

SUMMARY OF BACKGROUND DATA

Other investigators have reported the correlation between radiologic evaluation and anatomic dissection. However, in those studies the radiologic evaluation was not independent of the surgeons placing the screws. There has been no comment in the literature regarding particular screw malpositions that would lead the surgeon into a false sense of successful screw placement.

METHODS

Pedicle screws were placed in cadaver spines, and biplanar roentgenograms of the specimens were evaluated by independent observers. The results of the roantgenogram evaluation then were compared to those of the anatomic dissection.

RESULTS

The accuracy of roentgenogram evaluation varied from 73% to 83%, depending on the experience of the surgeon grading the roentgenograms. Screws misplaced medially into the spinal canal are more likely to give the surgeon a false sense of successful screw placement.

CONCLUSIONS

The surgeon must not rely solely on the roentgenograms, but instead continue to use tactile sensory skills, anatomic knowledge, and additional modalities such as electromyography monitoring.

Familial predisposition for degenerative disc disease. A case-control study

STUDY DESIGN

This case-control study was undertaken to determine if relatives of patients who had been admitted for surgery for degenerative disc disease-related problems were at increased risk for lower back pain or sciatica.

OBJECTIVES

To determine if familial factors play a role in placing a person at risk for development of degenerative disc disease of the lumbar spine.

SUMMARY OF BACKGROUND DATA

It is known that smoking and various occupational factors can place a person at risk for degenerative disc disease problems. It is not known if a familial predisposition may also exist.

METHODS

The family members and relatives of 65 patients who had undergone surgery for lumbar degenerative disc disease were interviewed with a standardized questionnaire and compared with a control group of 67 patients who had been admitted to hospital for non-spine-related orthopedic procedures. The same interview and standardized questionnaire was used for both groups by a single observer.

RESULTS

In the study group of 65 patients who had undergone surgery for degenerative disc disease, 44.6% were noted to have a positive family history, whereas 25.4% of the patients in the control group had a positive family history. Eighteen and one-half percent of relatives in the study group had a history of having spinal surgery, compared with only 4.5% of the control group.

CONCLUSIONS

The results indicate that a familial predisposition to degenerative disc disease can exist along with other risk factors.

Biomechanical comparison of the dewar and interspinous cervical spine fixation techniques

STUDY DESIGN

This study evaluates and compares the stiffness of two cervical spine fixation techniques.

OBJECTIVES

This biomechanical study was carried out to compare the interspinous and Dewar cervical spine fixation techniques.

SUMMARY OF BACKGROUND DATA

Interspinous wiring is a commonly used method of fixation in the cervical spine. The Dewar technique is less commonly known and practiced, and clinical experience has suggested that it may be a more stable technique.

METHODS

Cervical spine specimens stabilized with the interspinous and "Dewar" techniques were biomechanically tested in flexion and in torsion. Stiffness and energy absorption under moderate loads were compared. The Dewar technique uses contoured double corticocancellous iliac grafts as internal grafts/splints fixed to the spine with threaded pins and wire. The interspinous technique is a single interspinous wire loop. Eleven fresh human cervical spines were harvested from cadavers. The spines were destabilized at C4-C5 by sectioning all tissue except the anterior longitudinal ligament. Each fixation technique was applied alternatively and tested on each spine.

RESULTS

In torsion testing (n = 5), the Dewar fusion was 61% stiffer than the interspinous technique (P < 0.02). Dewar: 11.3 N/mm (s.d. 4.9 N/mm) and interspinous: 8.4 N/mm (SD 3.3 N/mm). In flexion testing (n = 6), the Dewar technique was 35% stiffer than the interspinous technique (P < 0.10). Dewar: 655.4 Nmm/degree (SD 293 Nmm/degree) and interspinous: 406.8 Nmm/degree (SD 113.0 Nmm/degree). Energy absorption with the interspinous technique was greater in flexion (P < 0.10) and in torsion (P < 0.005), indicating more deformation with the interspinous technique. There was no statistically significant difference between the means of specimens tested first and those tested second independently of the fixation technique.

CONCLUSIONS

These tests indicate that the Dewar cervical spine fixation is stiffer than the single interspinous wire in both flexion and particularly torsion. This project is the only biomechanical study of the Dewar technique that we are aware of, and the results support the clinical findings regarding the effectiveness of this technique.

Results of intervertebral diskectomy without fusion at L4-5 versus L5-S1

The results of diskectomy without fusion at L4-5 were compared with those at L5-S1. Strict indications for surgery had been applied to each group. Evaluation was carried out using the Oswestry Disability scale, as well as a modified Smiley-Webster scale, and a subjective improvement rating scale, as well as documenting work status, whether any future surgery was required, and other factors. Results were placed into categories based on these evaluation methods and were analyzed statistically. Average follow-up was 51 months with a minimum of 24 months. Overall excellent and good results occurred in 81% of patients in both groups. No difference in reoperation rate was detected between the two groups. Women were more likely to undergo a subsequent procedure, usually fusion. Equally satisfactory results can be obtained at L4-5 and L5-S1 if strict selection criteria are used.

Magnetic resonance imaging. Use in patients with low back or radicular pain

With the current emphasis on cost containment, it is important to order the single best diagnostic test when clinical uncertainties must be resolved. Magnetic resonance imaging is currently the optimal imaging modality to provide the maximum amount of information when evaluating patients with suspected spinal disorders. A comprehensive magnetic resonance imaging study is needed along with a subspecialty interpretation to provide the greatest amount of useful clinical information.

Radiographic assessment for patients with low back pain

Guidelines for radiographs of the lumbar spine are established. In general, radiographs are not believed to be necessary for a first episode of low back pain present for less than 7 weeks. Exceptions to this include various medical or physical findings, which are listed. In general, anteroposterior and lateral views only should be done initially. Indications for other views are discussed.

The results of surgical treatment for adult scoliosis

This study was done to define and characterize those adult patients with scoliosis who will have problems of pain and/or progression leading to a surgical procedure and to review the results of these surgical procedures. The authors reviewed the cases of 49 adult patients who had undergone surgical treatment for scoliosis (average follow-up, 34 months; range, 24-140 months). The patients were categorized according to age, which allowed analysis of the data comparing age and the incidence and level of pain, age versus the degree of curvature, and age versus the incidence of progression. The relative incidence of pain and progression as indications for surgery were found to vary with respect to age. In the younger groups, progression was more often the indication for surgery than in the older groups. The younger groups also had larger curves than did the older groups, on average. The degree of pain was not found to correlate with the magnitude of the deformity. Surgical complications occurred in 20 patients; however, 14 of these were minor complications during the perioperative period, which did not result in any sequelae. Surgical treatment can be done with a relatively low serious complication rate and good results in terms of pain relief and reasonable correction of the deformity.

Capitellocondylar total elbow replacement in rheumatoid arthritis. Long-term results

We evaluated the long-term results of 202 capitellocondylar total elbow replacements that had been performed, from July 1974 through June 1987, in 172 patients. The duration of follow-up averaged sixty-nine months (range, twenty-four to 178 months). At the most recent follow-up examination, use of a 100-point rating score demonstrated an improvement from an average preoperative score of 26 points (range, 2 to 50 points) to an average postoperative score of 91 points (range, 45 to 100 points). The most improvement occurred in the categories of relief of pain, functional status, and range of motion in all planes except extension. The improvements in these categories and in the roentgenographic appearance that were seen in the early postoperative period did not deteriorate with time. The average preoperative arc of motion at the elbow ranged from -37 degrees of extension to 118 degrees of flexion. The average postoperative arc of motion at the elbow ranged from -30 degrees of extension to 135 degrees of flexion. Supination improved from 45 degrees preoperatively to 64 degrees postoperatively; pronation improved from 56 degrees preoperatively to 72 degrees postoperatively. The roentgenograms showed a radiolucent line adjacent to eight humeral and nineteen ulnar components; most of the lines were incomplete and one millimeter wide or less. Revision of the prosthesis was necessary in three elbows (1.5 per cent) because of loosening without infection, and in three additional elbows because of dislocation of the prosthesis. Complications included deep infection in three elbows (1.5 per cent); problems related to the wound in fifteen (7 per cent); permanent, partial sensory ulnar-nerve palsy in five (2.5 per cent); permanent, partial motor ulnar-nerve palsy in one (0.5 per cent); and dislocation in seven (3.5 per cent).

Spinal stenosis with scoliosis

A retrospective review was carried out on 40 patients who met the criteria of 1) having a significant lumbar scoliosis associated with spinal stenosis, with symptoms of neurogenic claudication; and 2) having been treated with posterior decompression and pedicular screw fixation techniques. The average age of the patients was 61.5 years (range, 38-77 years), and 25 of the 40 patients were female. Eighty-eight percent of the patients had significant back pain in addition to lower extremity pain. All patients had pedicular screw fixation at all levels. Zielke instrumentation was used in 24 patients, Cotrel-Dubousset instrumentation in 8 patients, and Texas Scottish Rite Hospital instrumentation in the remaining 8 patients. After surgery, there was marked improvement in regard to pain status: 34 patients (83%) had severe pain before surgery, with 38 patients (93%) reporting mild or no pain at follow-up. Average length of follow-up was 44 months (range, 24-61 months). There were no deaths and no instrument-related failures or pseudarthroses noted in this series. A mean correction of the deformity of 19 degrees was obtained. Average scoliosis was 37 degrees before surgery and 18 degrees at follow-up.

Acute tumor lysis syndrome after intrathecal methotrexate administration

A 44-year-old man had acute tumor lysis syndrome after a single dose of intrathecal methotrexate was administered for lymphomatous meningitis (high-grade, small noncleaved B-cell) in the setting of untreated systemic disease. The metabolic derangements reversed completely with conservative therapy and did not recur with subsequent treatment. Intrathecal methotrexate administration results in potentially toxic systemic methotrexate levels which persist longer than an equivalent systemic dose. Active central nervous system lymphoma may increase the duration of toxic levels in the circulation and contribute to the peripheral effects of the drug. The pathogenesis of tumor lysis syndrome in this patient and the mechanisms of systemic toxicity of intrathecal methotrexate are discussed.

The accuracy of tibial intramedullary alignment devices in total knee arthroplasty

The accuracy of a tibial medullary alignment device is assessed radiographically in 30 varus and 30 valgus knees undergoing total knee arthroplasty. The results suggest that although the device is reliable and accurate for varus knees, it may lead to malalignment of up to 5 degrees in valgus knees. Overall neutral alignment was achieved in 83% of the varus knees and 37% of the valgus knees. Tibial bowing was the main source of error and was present in 66% of the valgus knees, with mean of 3 degrees. Preoperative long films or cross-checking with external alignment devices is recommended to assure neutral alignment in genu valgus deformity.

Age-related changes in the human femoral cortex

Bone undergoes structural changes with aging, but the nature of qualitative changes remains to be established. Blocks of midshaft femur were taken at autopsy from men of four different age groups: 20-25 years, 40-45 years, 60-65 years, and 80-85 years. Each femoral specimen was analyzed by density fractionation, a technique that allows the separation of bone by extent of mineralization and maturity. In the 20-25 group, lower density bone predominates. The 40-45 group is characterized by more highly mineralized bone with an increase in the 2.1-2.2 g/cc fraction. At 60-65 years, an increase in the lower density fraction was found, indicating an increase in new bone formation. At 80-85 years, there is an increase in the highest density bone (2.2-2.3 g/cc), which may represent regions of interstitial bone not properly removed through remodeling processes. Chemical studies did not reveal any change in Ca, P, Ca + PO4, or Ca/P molar ratio with respect to age. X-ray diffraction studies show no changes in apatite crystal size with respect to age or degree of mineralization. Morphological studies documented increased remodeling activity and endosteal trabecularization in the older age groups, as well as increased intracortical porosity. An increase in the highest density fraction with aging may represent a pool of bone mineral that is less accessible to remodeling, which may be the interstitial bone.

Interobserver variability in grading Perthes' disease

Fifteen independent observers of three levels of experience (consultant staff, fellows, residents) assessed 40 radiographs of children presenting with Perthes' disease using the Catterall and the Salter-Thompson grading systems. Each observer was supplied with descriptions and illustrations of the classifications and each hip was grouped by both systems by each observer. The results were statistically analysed using 'kappa' statistics. The level of interobserver agreement was higher for the Salter-Thompson system and correlated with the level of experience of the observer. Both systems can give acceptable levels of interobserver agreement, but the Salter-Thompson grouping is simpler and easier to apply in the earlier stages of the disease when treatment must be decided, and has a higher degree of reproducibility amongst more experienced observers.

Bone mineral in the castrated rat model of osteopenia

The effects of castration on cortical bone structure and chemistry were studied in male Wistar rats of two age groups, 8 and 24 months. Some rats were castrated and some were sham operated (control) in each group. All animals were killed after 4 months. Although no changes in serum chemistry, bone chemistry, or bone histology could be found, the young castrated animals versus controls showed less density of bone mineral as determined by the density fractionation technique and smaller crystallite size of mineral particles as determined by x-ray diffraction line-broadening analysis. These changes, indicative of less mature bone formation, were not observed in mature castrated or control rats despite a decreased amount of bone compared with young rats. In this model, castration appears to affect bone mineral quality in young but not in old animals.