Spinal surgery in spinal muscular atrophy

Fifteen patients with surgical treatment of spinal muscular atrophy were reviewed. The curve pattern was thoracic in 3, thoracolumbar in 11, and double thoracic and thoracolumbar in 1. Follow-up averaged 31 months. Eleven patients underwent posterior spinal fusion with Harrington instrumentation, with segmental wiring in four, and two had Luque instrumentation. The average age at time of surgery was 14.4 years. The average curve correction was 48%; that with the pelvic obliquity corrected, 63%. Surgery is best done when the curve is approximately 50-60 degrees, and Luque sublaminar wiring of Harrington or Luque rods with no external support appears to be the procedure of choice.     

Sublaminar wiring stabilization to prevent adjacent segment degeneration after lumbar spinal fusion

Introduction  Adjacent segment degeneration (ASD) is a complication of lumbar spinal fusion. There are some reports on the cause of this degeneration but none concerning its prevention. We performed sublaminar wiring stabilization to prevent ASD after posterolateral lumbar spinal fusion with instrumentation. The purpose of this study was to prospectively evaluate the efficacy of this procedure. Patients and methods  Between 2003 and 2004, 54 consecutive patients with lumbar spinal canal stenosis and multilevel instability of the lumbar spine underwent posterior decompression and posterolateral fusion with instrumentation. The mean age at the time of surgery was 66.7 ± 1.3 years, and the mean follow-up period was 40.0 ± 1.1 months, with a minimum of 29 months. Twenty-seven of the patients underwent conventional sublaminar wiring stabilization at the cephalad segment adjacent to the site of fusion to prevent ASD (group A), and the other 27 patients did not (group B). Some items were assessed, including clinical outcome using Japanese Orthopaedic Association (JOA) score, sagittal global lumbar alignment, and segmental motion in flexion–extension radiographs of the cephalad vertebral body adjacent to the site of fusion. Results  There were no significant differences in JOA scores between two groups, but 2 patients in group B underwent subsequent surgery due to ASD. Sagittal lumbar alignment did not change in group A but was significantly decreased in group B. With respect to segmental motion in flexion–extension radiographs, group A showed a significant decrease from 6.9° before surgery to 3.4° after surgery, on the other hand group B showed a significant increase from 5.6° before surgery to 8.4° after surgery. Conclusions  In this study, it was suggested that sublaminar wiring stabilization significantly reduces the range of motion of the adjacent segment and preserves sagittal lumbar alignment, which lead to prevention of ASD. The clinical outcome of the subsequent surgeries is relatively poor, so it is important to prevent ASD by any prevention such as sublaminar wiring stabilization.     

Contoured Harrington instrumentation in the treatment of unstable spinal fractures. The effect of supplementary sublaminar wires

Twenty-nine patients with major fractures and fracture-dislocations of the thoracic and lumbar spine were treated by spinal fusion and contoured Harrington distraction instrumentation. Two groups of patients were identified. Group I (16 patients) had sublaminar wires. Group II (13 patients) had no wiring. Satisfactory alignment was achieved in all patients. There were several complications in both groups. None of the patients in Group I had postoperative cast immobilization. The addition of sublaminar wiring appears to eliminate the need for rigid external immobilization and is beneficial only for patients who cannot tolerate body casts. This technique is a disadvantage, however, when a short-length fusion is desired.     

Luque rod stabilization for metastatic disease of the spine

Instability of the spine caused by metastatic spread of primary tumors represents a serious risk for spinal cord or nerve root compression. In order to restore stability and relieve neural compression, a variety of surgical techniques originally used for reduction of nonpathologic spinal fractures have been applied to the problem of spinal metastases. Recently, we have utilized a technique developed primarily for correction of scoliosis to the treatment of metastatic spinal fractures. Six patients with spinal instability and neural compression secondary to metastatic tumors had segmental spinal stabilization with Luque rods, sublaminar wiring, and methyl methacrylate. Restoration of stability was successful in all cases with alleviation of preoperative pain and return to full activity. No evidence of instability occurred in this group of patients. As demonstrated by this experience and that of a few other small series, Luque rod stabilization provides a valuable addition to the techniques available for stabilization of metastatic fractures of the spine. Although the precise role of Luque rod segmental spinal stabilization in treatment of metastatic disease of the spine continues to be defined, thus far it has proved beneficial for cases of multiple vertebral body involvement or instability beyond one vertebral level.     

The treatment of spinal fractures with Harrington compression rods and segmental sublaminar wiring. A dangerous combination

The increasing use of more rigid internal fixation constructs for spinal fractures, especially in association with spinal cord injury, has led surgeons to combine sublaminar segmental wiring with Harrington instrumentation systems. Two clinical cases whose neurologic condition deteriorated postoperatively were shown to have sustained direct cord injury by the combination of Harrington compression rods with segmental sublaminar wiring. Myelographic and surgical evidence of hook protrusion into the spinal canal with direct cord injury is presented. Laboratory spine simulations duplicating the clinical situation did demonstrate that sublaminar wiring of the Harrington compression rod system caused the standard hooks to protrude dangerously into the spinal canal. Caution should be exercised not to combine Harrington compression rods with segmental sublaminar wiring.     

Posterior spinal instrumentation and fusion of a neuromuscular scoliosis in a patient with autosomal dominant osteopetrosis

STUDY DESIGN: A case report of a patient with autosomal dominant osteopetrosis and neuromuscular scoliosis who required surgical instrumentation and fusion of her spine. OBJECTIVE: To illustrate the surgical technique and long-term outcome in this rare form of spinal deformity. SUMMARY OF BACKGROUND DATA: Osteopetrosis is a group of rare skeletal dysplasias characterized clinically by skeletal osteosclerosis that is classically described in appearance as "marble bone." Despite the ubiquitous involvement of the vertebra, clinical manifestations of spinal involvement are uncommon. We present the case of an osteopetrotic patient with neuromuscular scoliosis who required surgical correction of her progressive deformity. There are no prior reports in the literature concerning operative or nonoperative management of scoliosis in this patient population. METHODS: The surgical technique utilized as well as the patient's response to surgical management of her scoliosis is presented with 5 year follow-up. RESULTS: The patient underwent a successful T4 to L1 posterior spine fusion and instrumentation using Luque rods, sublaminar wires and allograft bone augmentation. At 5 years following her index procedure, she is clinically and radiographically fused. CONCLUSION: Patients with osteopetrosis present unique surgical challenges during surgical correction of spinal deformities. The use of segmental sublaminar wires with 1/4-inch rods and crosslinks afforded stable fixation despite poor bone quality. Allograft bone combined with postoperative bracing resulted in a well-maintained correction and a solid fusion. Five year follow-up and continued radiographic evidence of stable fusion indicate that the presented approach can lead to a successful outcome in the osteopetrotic patient population.     

Harrington instrumentation with spinous process wiring for idiopathic scoliosis

To provide the stability of segmental spinal instrumentation without the risk associated with the passing of sublaminar wires, a technique of SSI was developed that uses the base of the spinous process as a site for purchase. To provide a broad attachment to the spinous process, a button-wire implant was developed. The rods used are a Harrington distraction rod for the concave side of the curve and a Luque rod for the convexity. Both are attached to the spine at each level by the button-wire implant. Biomechanical testing confirms that the implant provides load sharing, an advantage over wire alone, and that the instrumented spine is stable when compared with other systems. Clinical review showed approximately 60 per cent correction of the average curve, a small correction loss, and a better sagittal alignment than achieved previously with Harrington distraction alone. Complications were few.     

Postoperative neurological deficits in segmental spinal instrumentation. A study using spinal cord monitoring

We retrospectively analyzed the postoperative neurological complications in 137 patients who underwent a posterior spine fusion for scoliosis and had concomitant somatosensory cortical evoked-potential spinal-cord monitoring. The patients were divided into three specific operative groups: group 1, forty-nine patients who had a Harrington rod with segmental wiring (segmental spinal instrumentation); group 2, twenty patients who had Luque segmental spinal instrumentation; and group 3, sixty-eight patients who had a Harrington rod without segmental spinal instrumentation. There were neurological complications in twelve (17 per cent) of the sixty-nine patients in groups 1 and 2. Three patients (4 per cent) had a major injury to the spinal cord and nine patients (13 per cent) had only transient sensory changes. No difference was apparent between group 1 and group 2 in the degree of operative correction of curves or in the incidence of neurological complications. The one neurological complication (1.5 per cent) that occurred in the sixty-eight patients in group 3 was a Brown-Séquard syndrome. The factors related to increased risk for spinal cord injury in groups 1 and 2 included: (1) the passage of sublaminar wires in the thoracic and thoracolumbar spine, (2) intraoperative correction exceeding the preoperative bending correction, and (3) the surgeon's lack of adequate experience with the technique. With spinal cord monitoring we were able to predict the impending major neurological deficits, but the transient (sensory) changes that may be associated with segmental wiring were less reliably predicted.     

Neurological complications in segmental spinal instrumentation: analysis of 750 patients

The authors report on neurological damage caused by the use of sublaminar segmental fixation in the correction of vertebral deformities. Three groups were reviewed: 600 patients instrumented with Harrington rods and segmental wiring, 50 patients treated with the Hartshill system and 100 patients instrumented with Luque bars. All of the patients were operated on using sublaminar wiring fixation. We report two transitory neurological complications among the 600 patients with Harrington rod instrumentation and segmental wiring, two permanent neurological deficits among the 50 cases treated with the Hartshill system and none among the 100 patients instrumented using Luque bars. The purpose of this study is to analyse the causes of these neurological complications, which occurred late in all four of the cases described.Presented at the ESDS meeting, Birmingham, 1994, and selected for full publication     

Spinous process segmental instrumentation for scoliosis

Spinous process segmental instrumentation (SPSI) for spinal fusion was devised in 1983 by Drummond et al. in an attempt to achieve the stability of segmental fixation without the known neurologic risks of passing sublaminar wires. We used SPSI in 75 scoliosis patients. Sixty-one had idiopathic scoliosis, 12 had neurogenic scoliosis, and 2 had congenital scoliosis. There were no deep infections, pseudarthroses, or neurologic complications. Two patients experienced upper hook dislodgement with 10 degrees loss of correction. We concluded that SPSI can achieve the correction of Harrington rod instrumentation and the stability of Luque rod segmental instrumentation, without the neurologic risk of sublaminar wiring.     

Lumbar sagittal alignment after fusion with a threaded interbody cage.

STUDY DESIGN: Records of 111 patients randomly selected from a population who received an interbody fusion cage during a clinical Investigation Device Exemption trial (BAK/L) yielded 126 operative levels and were retrospectively assessed. OBJECTIVES: This study examined lumbar spine sagittal alignment and clinical outcomes before and 2 years after fusion surgery. SUMMARY OF BACKGROUND DATA: Lumbar lordosis is important in spinal sagittal alignment and balance, especially the L4-S1 area. Perceived consensus is that anatomically correct lumbar lordosis is desired and that a loss of lumbar lordosis may lead to spine pathology. There is little information on lumbar lordosis after interbody fusion. METHODS: A random sample of 111 patients who received a cylindrical cage implant (total pool of 947 patients) yielded 126 operative lumbar segments. There were 52 posterior approaches and 59 anterior approaches, and all cages were placed in the L4-L5 or L5-S1 levels. Preoperative and 2-year follow-up lateral radiographs were measured for segmental lordosis. Cage position was measured relative to the posterior longitudinal ligament. Segmental lordotic change was correlated to clinical outcome at the 2-year follow-up. RESULTS: Preoperative lordosis was different as a function of surgical approach. There was a significant 2-year decrease in lordosis with the posterior approach group; however, all intervertebral angles were within typical ranges. Clinical outcomes were significantly improved 2 years postsurgery. There was no correlation between changes in lordosis and clinical outcomes. CONCLUSIONS: Interbody lumbar fusion with a threaded cylindrical cage does not appear to have any clinically relevant effects on segmental lordosis, which is maintained within anatomically normal levels. Clinical outcome measures show significant postsurgery improvement, and changes in lordotic angles are not predictive of clinical outcome.     

Combined anterior and posterior fusion for spinal deformity in myelomeningocele

Since 1973, 50 of 54 children have been treated by the author with a combined anterior and posterior fusion. Twenty males and 34 females, ranging in age from 1 to 16 years, have been followed for a mean period of 5.5 years. Sixteen patients with a kyphosis averaging 113 degrees (range, 77 to 170 degrees) had correction of deformity to a mean of 35 degrees. Thirty-seven patients with a scoliosis averaging 73 degrees (range, 20 to 135 degrees) had correction to an average of 34 degrees (range, 0 to 75 degrees). There were 4 cases of deep wound infection successfully treated with drainage and antibiotics and only one case required implant removal after fusion/maturation. A pseudarthrosis was noted by radiograph in 6 patients, 3 of whom had isolated asymptomatic lumbosacral pseudarthroses. Three patients had pseudarthrosis at the thoracolumbar junction. These required repair and were successfully treated by supplemental posterior fusion resulting in an overall pseudarthrosis rate of 5.7%. Anterior fusion of the dysraphic spine allows greater correction of both spinal deformity and pelvic obliquity in addition to contributing significant strength to the fusion mass. Segmental spinal instrumentation with sublaminar and pedicular wiring to custom-contoured Luque rods provides excellent correction and immediate postoperative stability.     

The migration of a broken luque rod: a case report

An exceedingly rare complication of Luque segmental spinal instrumentation in spinal fractures is described. A patient was treated for fractures of the eighth and ninth thoracic vertebra associated with traumatic paraplegia using Luque segmental spinal instrumentation. Ten years postoperatively, broken rods and sublaminar wires were found. One of the broken rods migrated caudad penetrating the sacrum and protruding into the pelvic cavity. The rod had projected into the rectum, and was extracted through the wall of the rectum and the anus. This case report emphasizes the importance of careful surgical technique and long-term follow up for patients who had undergone spinal instrumentation surgery.     

Luque rod instrumentation in the treatment of adolescent idiopathic scoliosis. A comparative study with Harrington instrumentation

Adolescent idiopathic scoliosis in 152 patients was treated by Luque L-rod instrumentation and early mobilisation without external support. This series was compared with a matched group of 156 patients treated by Harrington instrumentation and immobilised in an underarm jacket for nine months. All the operations in both groups were performed by one surgeon and the patients were followed prospectively for more than two years. Correction of the scoliosis in the frontal plane was similar in both groups. However, the normal sagittal contour was better maintained with Luque rods, especially in the thoracolumbar and lumbar regions, and provided less loss of correction than with Harrington rods. Neither method significantly derotated the scoliosis. All the patients with Luque instrumentation developed a solid fusion despite breakage of the sublaminar wires at one or two levels in 4.9%. There were no major neurological complications with either type of instrumentation.     

Analysis of lumbar lordosis in posterior spine fusions for idiopathic scoliosis

Previous reports are inconclusive regarding changes in the lumbar region after Harrington rod distraction and posterior spinal fusion for idiopathic scoliosis. The purpose of this study was to evaluate the effects of spinal fusion on the lumbar region, particularly the overall lumbar lordosis, the lumbar lordosis in and below the fused segment, the sacro-horizontal angle, and the sagittal plane alignment of the spine. Sixty-six patients under 21 years of age with idiopathic scoliosis who had spine fusion extending to the lumbar vertebrae using only Harrington distraction instrumentation were evaluated. The total lordosis, sacro-horizontal angle, and sagittal plane alignment remained relatively constant. The lordosis within the fusion decreased, and lordosis caudal to the fusion, including the last fused vertebra, increased as the lower hook placement site moved caudally.     

Measurements of lumbopelvic lordosis using the pelvic radius technique as it correlates with sagittal spinal balance and sacral translation.

BACKGROUND CONTEXT: Maintenance of normal lumbar lordosis is important in the treatment of spinal disorders. Many attempts have been made to quantify normal sagittal spinal alignment and lordosis using a C7 plumb line and segmental angulations of the spinal vertebrae. Little attention has been given to pelvic compensation as it correlates to lumbar lordosis and overall sagittal spinal alignment. Better methods of measuring lordosis, which correlate with sagittal spinal balance and pelvic compensation, are needed in treating patients with spinal disorders. PURPOSE: To determine the correlation between lumbopelvic lordosis, pelvic rotation and sagittal spinal balance and standardize a method for measuring lumbopelvic lordosis, sacral translation, and sagittal spinal alignment. STUDY DESIGN: Sagittal alignments using the C7 plumb line, Cobb angles, sacral plumb line and the pelvic radius (PR) technique were used to measure standing 36-inch lateral radiographs of patients with various spinal disorders. PATIENT SAMPLE: A review of the records identified 62 patients with various spinal pathologies presenting to the (RGW) spine clinic that had standing lateral spine radiographs. Only radiographs that allowed positive identification of the C7 vertebral body, the entire thoracolumbar spine, the sacrum and both femoral heads were studied. These criteria allowed inclusion of 28 subjects in this study. The final population had 12 women and 16 men with an average age of 52 years (SD, 16.6 years; range, 20 to 84 years). OUTCOME MEASURES: No outcomes measures were used in this study. METHODS: Measurements for sagittal spinal balance and lumbopelvic lordosis were made on 36-inch standing lateral radiographs of adult patients. Measurements included the C7 plumb line, segmental angulations of spinal vertebrae (Cobb angles), sacral translation and the PR technique for lumbopelvic lordosis. Data were analyzed for significant correlation between lumbopelvic lordosis, sagittal spinal balance, sacral translation and total segmental lumbar lordosis using the Cobb method. RESULTS: Our population averaged 50 degrees of total segmental lumbar lordosis from L1 to S1 (SD, 14.3; maximum, 89.5; minimum, 17.9). Nearly 75% of total segmental lumbar lordosis measured from L1 to S1 can be accounted for through the L4 to S1 superior end plates and 47% through L5 to S1 superior end plates in our population. Total segmental lumbar lordosis correlated with total thoracic kyphosis (r=0.45, p=.008). Total segmental lumbar lordosis measured by the Cobb method significantly correlated with sagittal spinal balance (r=-0.35, p=.022) and sacral translation (r=0.41, p=.016). Measurements for lumbopelvic lordosis significantly correlated with sagittal spinal balance (r=-0.33, p=.042), sacral translation (r=-0.70, p=.00002) and total segmental lumbar lordosis (r=0.82, p<.000001). Measurements for sacral translation and sagittal spinal balance also correlated significantly (r=0.35, p=.034). CONCLUSIONS: Sacral translation, the C7 plumb line and lumbopelvic lordosis are useful measures for sagittal spinal balance. Lumbopelvic lordosis and sacral translation can be correlated to the sagittal spinal balance. Understanding these measurements and the range of lumbopelvic compensation can be extremely helpful in treating patients with spinal pathology and in avoidance of flatback deformity. Application of these measures would be especially helpful in the treatment of patients with spinal fusion, degenerative spondylosis, disc disease, fractures, and in the prevention of sagittal malalignment.     

Shear fracture-dislocations of the thoracic and lumbar spine associated with forceful hyperextension (lumberjack paraplegia).

Twelve patients sustained a shear fracture-dislocation of their thoracic or lumbar spines by a hyperextension mechanism of injury. Ten male and two female patients were injured; their average age was 29 years (range, 22 months to 56 years). Ten fracture-dislocations occurred in the thoracic spine, one at the thoracolumbar junction, and one in the lumbar spine. Eleven patients had complete paraplegia, and one had incomplete paraplegia at the time of injury. Dural tears were found in six of the patients. Eleven patients were treated by posterior spinal fusion with instrumentation, and one was treated with a brace. Three patients were treated with Harrington distraction rods alone, six had Harrington distraction rods supplemented with a midline Harrington compression rod or interspinous wiring, and two were treated with Cotrel-Dubousset instrumentation. No patient was lost to follow-up. The average length of follow-up was 3.5 years (range, 1-9 years). Six of the patients treated with Cotrel-Dubousset instrumentation or Harrington distraction rods supplemented with either a midline compression rod or interspinous wiring healed anatomically; two patients developed pseudarthroses. None of the patients treated with Harrington distraction rods alone healed in an anatomic position. The use of Harrington distraction rods alone was associated with overdistraction and nonanatomic alignment of the spine. The disruption of the anterior stabilizing structures of the spine associated with hyperextension injuries necessitates the use of instrumentation that can stabilize the spine and prevent overdistraction. This injury can be successfully treated with Cotrel-Dubousset or Harrington distraction rods supplemented with either a midline compression rod or interspinous wiring.     

Segmental spinal instrumentation in idiopathic scoliosis. A preliminary report

Eighty-six patients with idiopathic scoliosis who underwent a posterior spinal fusion using sublaminar segmental spinal instrumentation were analyzed retrospectively. There were two operative groups: group 1, 66 patients who had Harrington rod instrumentation and segmental wiring, and group 2, 20 patients who had Luque rod instrumentation. The clinical and radiographic data of the two groups were similar except for the passage of more sublaminar wires and increased intraoperative blood loss in group 2. Twenty intraoperative or postoperative complications occurred in 19 patients (22%) including 14 neurologic complications. Three patients (3%) had major spinal cord injuries, while 11 patients (13%) had transient sensory changes. There was no significant difference in the incidence of neurologic complications between group 1 or group 2. The remaining intraoperative complications were due either to anesthesia, positioning during surgery, or technique (dural tear). Late complications occurred in two patients in group 1 only: one each with rod breakage and hook displacement. Only one patient (1%) has required additional surgery. Our results indicate that although segmental instrumentation can be beneficial in idiopathic scoliosis, the incidence of complications, primarily neurologic, will be higher than expected. The major reason appears to be surgeon inexperience with passage of sublaminar wires. As experience increases, the incidence of complications declines and becomes comparable with conventional Harrington rod instrumentation alone.     

Adult idiopathic scoliosis treated with Luque or Harrington rods and sublaminar wiring

We reviewed the results of spinal arthrodesis that was performed, with sublaminar wires that were attached to either double L-shaped Luque rods or to a Harrington rod, in forty-two adults who had idiopathic scoliosis. The minimum length of follow-up was two years; the maximum, five years; and the average, three years. The average scoliosis measured 67 degrees preoperatively, was corrected to 37 degrees at operation, and was 44 degrees at the time of follow-up. The final correction averaged 34 per cent. A single Harrington rod and multiple sublaminar wires were used in thirty-one patients. Eighteen of the thirty-one patients had a posterior arthrodesis only and thirteen, a preliminary anterior arthrodesis followed by a posterior arthrodesis. Eleven patients had instrumentation with double L-shaped Luque rods; six of them had posterior arthrodesis only and five, a preliminary anterior arthrodesis followed by a posterior arthrodesis. One patient had neurological deficit that was related to the operation. Three patients had a pseudarthrosis, which was in the lumbar area in all of them. All three patients had had only a posterior operation. No statistically significant difference in the amount of final correction was demonstrated between the subgroups.     

Comparison of lumbosacral fixation devices

Fusion of L4 and L5 to the sacrum has a high incidence of success. Using conventional methods, nonunion is common when long scoliosis fusions are extended to the sacrum. Three methods of instrumentation for fusing the lumbar spine to the sacrum were compared on a spine simulator test stand. Harrington distraction rods from the sacral ala to L1, Luque rods from L1 to the sacrum, and Harrington compression rods from L1 to the sacrum were tested. The use of a spine instrumentation test stand discounted biologic variation in spinal structure. Sequential loading of each test stand-instrumentation construct in torsion, flexion, extension, and lateral bending gave stiffness constants (Ks) for each test mode. Test values had reproducibility of greater than 94%. Ks illustrates the inability of Harrington distraction rods to the sacrum to resist flexion and torsion, but the ability to resist lateral bend and extension. Harrington compression rod and Luque rod constructs have equivalent stiffness in flexion and torsion. Harrington compression rods efficiently resist extension, and Luque rods resist lateral bending. Harrington distraction rods have limited use in lumbosacral junction fixation other than to correct and resist lateral bending.