Progressive rotational dislocation in kyphoscoliotic deformities: presentation and treatment.

STUDY DESIGN: Progressive rotational dislocation of the spine has been described as the most serious evolutive risk of kyphoscoliosis. A retrospective chart review was conducted on 11 patients with this deformity. OBJECTIVES: To delineate the clinical and radiologic characteristics of this entity to facilitate early diagnosis and treatment. The outcome after treatment was analyzed to point out the rationale for appropriate treatment. METHODS: The characteristic radiologic feature was a short sharp angled kyphosis (average 112) at the junction of two lordoscoliotic curvatures. The etiology of the spinal deformity was neurofibromatosis in four patients and various dysplastic conditions in seven patients. Two patients had congenital vertebral defects. Structural weakness of the bone was therefore a basic feature. Neurologic impairment was identified in three patients (one complete, two incomplete). Four patients had a nonunion after a previous attempt at spinal fusion: two after a combined anterior and posterior fusion with an anterior approach from the convexity and two after a posterior fusion alone. All patients underwent complete circumferential stabilization through anterior strut-grafting and posterior fusion. An anterior approach from the concavity was performed systematically with tibial strut grafts inserted in a palisade fashion. Preoperative correction of the deformity was performed by progressive controlled elongation in a Stagnara elongation cast. Cotrel-Dubousset instrumentation was used in two patients, Harrington instrumentation was used in two patients, and cast immobilization alone was used in seven patients. RESULTS: The average follow-up period was 5 years 5 months. All but one patient achieved successful spinal fusion. Loss of correction at the latest follow-up evaluation was less than 3 degrees in nine patients. The two patients with incomplete neurologic deficits were improved, but the patient with the complete deficit remained unchanged after surgery. CONCLUSIONS: Awareness of the possibility of a progressive rotational dislocation in dystrophic forms of kyphoscoliosis should allow for an early diagnosis and stabilization. The percentage of patients having a neurologic deficit in this series was significantly less important than in the initial report. Early anterior strut grafting from the concavity of the scoliotic curvature and posterior fusion is recommended.

Iliosacral screw fixation for pelvic obliquity in neuromuscular scoliosis. A long-term follow-up study.

STUDY DESIGN: This was a retrospective review of a consecutive series of patients with neuromuscular spinal deformity who underwent posterior fusion and pelvic fixation using a long construct and an iliosacral screw. OBJECTIVES: To evaluate the risks and benefits of iliosacral screw fixation. SUMMARY OF BACKGROUND DATA: Neuromuscular scoliosis with pelvic obliquity poses one of the most challenging instrumentation problems, mainly because of the poor bone quality frequently found within the sacrum. Complications include failure of instrumentation, loss of sacral fixation, loss of lumbar lordosis, and a high rate of nonunion. METHODS: One hundred fifty-four patients with neuromuscular scoliosis and pelvic obliquity underwent posterior arthrodesis with pelvic fixation using an iliosacral screw. Anteroposterior scoliosis Cobb angle, frontal pelvic obliquity, and sacral inclination angle were measured before surgery, immediately after surgery, and at the 5-year and 3-month follow-up examination. Influence of etiology, severity of deformity, and associated anterior release at the scoliotic curve above also were assessed. RESULTS: Correction of scoliosis Cobb angle ranged from 53% to 70%, and loss of correction ranged from 3% to 14% at the last follow-up examination. Correction of pelvic obliquity ranged from 60% to 84%, and loss of correction was mild. Sacral inclination angle approached normal values in all patients, except for those with myelomeningocele who had preoperative pelvic retroversion. Loss of correction ranged from 0.3 degree to 5.4 degrees at the last follow-up examination. Complications and loss of correction mostly were encountered in patients with myelomeningocele and spinal muscular atrophy. CONCLUSIONS: Iliosacral screw fixation in neuromuscular scoliosis is technically standardized and easy and offers mechanically efficient and stable fixation.

The congenital dislocated spine.

STUDY DESIGN: The congenital dislocated spine has been defined as the potentially most serious form of congenital kyphosis with an abrupt single-level displacement of the spinal canal. A retrospective chart review was conducted on 19 patients with this deformity. OBJECTIVES: To delineate the clinical and radiologic characteristics of this entity, and to analyze the outcome after treatment. SUMMARY OF BACKGROUND DATA: An anterior failure of formation was the basic feature. Kyphosis was variable. Vertebral displacement in the frontal plane was present in seven patients, and sagittal displacement was constant. Mechanical instability was seen in 17 patients. Neurologic impairment was identified in 12 patients, and congenital paraplegia was seen in eight patients. An acute paraplegia occurred after minor trauma in one patient. METHODS: Seventeen patients were treated surgically. Thirteen patients underwent complete circumferential stabilization through anterior strut grafting and posterior fusion without instrumentation, usually before age 3 years. Neurosurgical decompression was done in four patients. RESULTS: The average follow-up period was 8 years, 6 months. Nonunion of the posterior fusion mass was detected and successfully treated in five patients. A solid fusion seemed to be obtained in all patients at last follow-up evaluation. The neurologic status after neurosurgical decompression remained unchanged in three patients and was improved temporarily in one patient. CONCLUSIONS: Avoidance of neurologic morbidity requires early diagnosis and stabilization. The authors recommend early anterior strut grafting and posterior fusion. Exploration of the posterior fusion mass should be done systematically.

Posterior spinal fusion in neuromuscular scoliosis using a tibial strut graft. Results of a long-term follow-up.

STUDY DESIGN: Risks and benefits of using a tibial graft for posterior spinal fusion in neuromuscular scoliosis were evaluated in a long-term follow-up study. A consecutive series of 72 patients underwent posterior spinal fusion for neuromuscular scoliosis. OBJECTIVES: Radiologic outcome was assessed to evaluate the quality of the spinal fusion. Patients were followed serially to detect donor site complications. Mean follow-up was 17 years and 8 months (minimum: 6 years, 6 months). SUMMARY OF BACKGROUND DATA: Mean age of the patients at the time of surgery was 15 years. Progression of the curvature was minimal at last follow-up (mean progression at last follow-up: lumbar curve, 4.5 degrees; thoracic curve, 5.3 degrees). Concerning donor site complications, four patients had a leg length discrepancy of less than 2 cm at last follow-up. This complication was related to tibial overgrowth at the donor site. METHODS: Solid fusion was defined in this long-term study as the absence of modification of the radiologic aspect at last follow-up in addition to the presence of a massive contagious trabecular fusion mass. RESULTS: The fusion appeared to be solid in all patients. No obvious pseudarthrosis could be documented. The constant successful outcome differs significantly from spinal fusion that uses bank bone. The absence of stress fracture was correlated to the low level of constraint in this essentially nonambulatory population. CONCLUSION: This experience indicates that the tibial graft deserves consideration in posterior spinal fusion for neuromuscular scoliosis.