Postoperative Spinal Deformity Research Articles

Lamina Osteotomy and Replantation With Miniplate Fixation for Thoracic Myelopathy Due to Ossification of the Ligamentum Flavum

Lamina osteotomy and replantation with miniplate fixation is often used to treat benign intradural tumors, effectively preventing nerve entrapment and postoperative spinal deformities. However, no studies report using this technique to treat thoracic myelopathy due to ossification of the ligamentum flavum (OLF). This article reports the clinical outcome of a series of 18 cases of contiguous multilevel OLF treated by lamina osteotomy and replantation with miniplate fixation.Eighteen consecutive patients at the authors' institution were treated between 2008 and 2010 for contiguous multilevel OLF. Clinical efficacy, operative time, blood loss, sagittal alignment, and complications were investigated. Japanese Orthopaedic Association scale scores improved from 4.7±1.4 preoperatively to 7.9±1.3 three months postoperatively and 8.8±1.3 at final follow-up (P<.01), with a mean recovery rate of 67.8%±13.1%. No significant kyphotic deformity occurred postoperatively, and local kyphosis in the treated area increased by a mean of only 1.9°±1.0° at final follow-up. No patient required additional surgery due to spinal canal reobstruction and progressive spinal deformity. Cerebrospinal fluid leakage occurred in 4 patients and resolved after repair. Pulmonary infection and deep venous thrombosis occurred in 1 patient who was discharged with no complications after routine treatment.Lamina osteotomy and replantation with miniplate fixation is an effective therapeutic option for thoracic myelopathy due to contiguous multilevel OLF compression. The technique provides adequate decompression and stabilized sagittal alignment and avoids invasion of the spinal canal by scar tissue.

Long-term surgical outcomes of cervical dumbbell neurinomas

Study designRetrospective case series. ObjectiveTo evaluate our treatment strategy for cervical dumbbell neurinoma. Summary of background dataIn treating cervical dumbbell neurinoma, possible difficulties include reoperation due to recurrent tumor, denervation due to nerve root resection, and postoperative spinal deformity due to extensive bony removal. MethodsWe reviewed 75 cases of cervical dumbbell neurinoma that were treated surgically between 1985 and 2006. Postoperative neurological deficits, effects of surgical margins on tumor recurrence, and surgical complications were investigated retrospectively. ResultsSensory and motor deficits due to resection of specific nerve roots appeared temporarily in 33 and 23% of all cases, and persisted in 8 and 8% at final evaluation, respectively. Total, subtotal, and partial resection was performed in 57, 13, and 5 cases, respectively. The total resection rate was low in the tumors that had large extraforaminal components. Of the subtotally resected 13 cases, only two cases of high tumor-growth rate required re-operation or showed tumor growth. Among the five partially resected cases, re-operation was necessary in two cases 13 and 15years later because of aggravated neurological symptoms due to tumor growth. Two patients who underwent C2 laminectomy developed kyphosis, and three patients who underwent facet joint resection and curettage of vertebral body lesions developed scoliosis. ConclusionTotal resection should be attempted for cervical dumbbell tumors. In cases where total resection was potentially of high risk, however, subtotal resection (within the capsule) was found to be a practical choice yielding favorable long-term outcome when the tumor growth rate (MIB-1 index) was low.

Postoperative spinal deformity after treatment of intracanal spine lesions

Surgical treatment of intracanal (both intramedullary and extramedullary) spine lesions requires posterior decompressive techniques in nearly all instances. Postoperative spinal deformities, most notably sagittal and coronal decompensation, are of significant concern for both the patient and the spinal surgeon. To review and define principles and features of spinal deformities after posterior spinal decompression for intracanal spinal lesions, and to define patients who may benefit from the concomitant spinal fusion. A systematic review of MEDLINE was conducted, including articles published between 1980 and 2011. Articles related to spinal deformities after posterior decompression for the treatment of intracanal spine lesions were identified. Ten articles metall inclusion and exclusion criteria. All were case series with limited evidence (Level IV). Many risk factors to deformity were implied but with limited evidence. Young age was the most commonly identified risk in these articles. Spinal deformity after posterior decompression is a common complication, most notably in children and young adults, after the removal of intramedullary tumors. Many risk factors have been implied to increase the postoperative development of spinal deformity, including young age, laminectomy extension, preoperative deformity, and extensive facet resection, among others. However, there is a lack of high-quality evidence to propose an algorithm for treatment or preventive measures. New studies with larger series of patients and standardized clinical outcomes are necessary to establish optimal treatment protocols.

Surgical results after unilateral laminectomy for the removal of spinal cord tumors.

ObjectiveTo reduce the risk of postoperative spinal instability or deformity, unilateral laminectomy (UL) has been recommended to remove spinal space-occupying lesions. The purpose of this study was to determine whether there were any advantages of UL for removal of spinal cord tumors.MethodsFrom May 1995 to May 2010, 94 patients with spinal cord tumors, who underwent tumor removal via UL in our institute, were enrolled in this study. Intramedullary spinal cord tumors were excluded. Simple radiographs were obtained for accessing the restoration of the spinal column. Spinal magnetic resonance imaging (MRI) was also obtained during the follow-up period to evaluate tumor recurrence.ResultsThere were 51 women and 43 men; their mean age was 47.8 years (range, 9-83 years). The mean follow-up period was 52.6 months (range, 24 month-16 years). The sites of the tumors were cervical in 21 cases, thoracic in 37, lumbar in 33, and sacral in 3. These cases included 85 intradural extramedullary (IDEM) and 9 extradural (ED) lesions. IDEM tumors consisted mainly of neurilemmomas (56.3%) and meningiomas (22.3%).Tumors were totally removed in 80 cases and subtotally removed in 14 cases. Postoperative neurological status was improved in 53 cases, unchanged in 31 cases, and worsened in 10 cases. During follow-up, MRI showed tumor recurrence in 4 patients. Histopathologically, three cases were meningiomas and one case was neurilemmoma. None of the patients showed spinal instability or kyphotic deformity at last follow-up.ConclusionUL is an optimal approach for providing sufficient exposure of spinal cord tumors without development of postoperative spinal instability and regional sagittal imbalance in any location of spinal column. In cases of meningioma, careful long-term follow up is needed due to it's relatively high recurrence rate after removal via UL.

Complications associated with the treatment for spinal ependymomas

Spinal cord ependymomas are rare neoplasms, comprising approximately 5% of all CNS tumors and 15% of all spinal cord tumors. Although surgery was once reserved for diagnosis alone, the evolution of surgical practices has elevated resection to the treatment of choice for these lesions. While technological advances continue to improve the capacity for gross-total resections and thus decrease the risk of recurrence, ependymoma spinal surgery still contains a variety of potential complications. The presence of neurological deficits and deterioration are not uncommonly associated with spinal cord ependymoma surgery, including sensory loss, dorsal column dysfunction, dysesthetic syndrome, and bowel and bladder dysfunction, particularly in the immediate postoperative period. Surgical treatment may also lead to wound complications and CSF leaks, with increased risk when radiotherapy has been involved. Radiation therapy may also predispose patients to radiation myelopathy and ultimately result in neurological damage. Additionally, resections of spinal ependymomas have been associated with postoperative spinal instability and deformities, particularly in the pediatric population. Despite the advances in microsurgical techniques and intraoperative cord monitoring modalities, there remain a number of serious complications related to the treatment of spinal ependymoma tumors. Identification and acknowledgment of these potential problems may assist in their prevention, early detection, and increased quality of life for patients afflicted with this disease.

Sagittal spino-pelvic alignment failures following three column thoracic osteotomy for adult spinal deformity

Three column thoracic osteotomy (TCTO) is effective to correct rigid thoracic deformities, however, reasons for residual postoperative spinal deformity are poorly defined. Our objective was to evaluate risk factors for poor spino-pelvic alignment (SPA) following TCTO for adult spinal deformity (ASD). Multicenter, retrospective radiographic analysis of ASD patients treated with TCTO. Radiographic measures included: correction at the osteotomy site, thoracic kyphosis (TK), lumbar lordosis (LL), sagittal vertical axis (SVA), pelvic tilt (PT), and pelvic incidence (PI). Final SVA and PT were assessed to determine if ideal SPA (SVA<4cm, PT<25°) was achieved. Differences between the ideal (IDEAL) and failed (FAIL) SPA groups were evaluated. A total of 41 consecutive ASD patients treated with TCTO were evaluated. TCTO significantly decreased TK, maximum coronal Cobb angle, SVA and PT (P<0.05). Ideal SPA was achieved in 32 (78%) and failed in 9 (22%) patients. The IDEAL and FAIL groups had similar total fusion levels and similar focal, SVA and PT correction (P>0.05). FAIL group had larger pre- and post-operative SVA, PT and PI and a smaller LL than IDEAL (P<0.05). Poor SPA occurred in 22% of TCTO patients despite similar operative procedures and deformity correction as patients in the IDEAL group. Greater pre-operative PT and SVA predicted failed post-operative SPA. Alternative or additional correction procedures should be considered when planning TCTO for patients with large sagittal global malalignment, otherwise patients are at risk for suboptimal correction and poor outcomes.

IATROGENIC SPINAL DEFORMITY

Patients with postoperative spinal deformities are being identified with increasing frequency as the number of instrumented spinal operations increases. Thus, it is important for the neurosurgeon to understand ways to minimize postoperative deformity and to understand its operative and nonoperative management. A variety of intra- and postoperative risk factors have been associated with postoperative deformity, including patient age, operative positioning, preoperative medical condition, and the use of prior radiation therapy. The evaluation of all patients who have been suspected of iatrogenic deformity should include a detailed physical examination, plain x-rays, and computed tomographic or magnetic resonance imaging, depending on the condition. Conservative therapy includes physical therapy and pain control, which may be effective in some patients. However, patients with flat-back syndrome typically require reoperation. A wide variety of reoperative procedures may be performed, depending on the area of the pathological deformity, extent of disease, and patient condition.

Multiple short-segment laminoplasties in children: a novel technique to avoid postoperative spinal deformity

Spinal deformity is a recognized important complication after laminectomies, especially in children. Even with laminoplasties, spinal deformity is a concern, especially when laminoplasties involve multiple levels. The author reports a novel technique to avoid postoperative spinal deformity using multiple short-segment replacement laminoplasties to access pathology over a long segment of the intraspinal space. The technique was used to evacuate an organized extradural hematoma from C4 to T9 in a 9-month-old infant with incomplete quadriplegia. Three separate, short-segment, and superiorly reflected laminoplasties (C5-C7; T2-T4; T6-T8) were performed, leaving intact the laminae (T1; T5) between each laminoplasty flap. At 1 year postoperatively, there was complete neurological recovery and no spinal deformity. The laminae re-fused anatomically. Multiple short-segment laminoplasties allow good access to a long intraspinal segment, may preserve the stability of the spine, prevent spinal deformity, allow good reconstitution of the laminar anatomy, and facilitate surgical stabilization should that be required in the future. This technique may be applicable to other intraspinal lesions, such as tumors.

Spinal deformity after resection of cervical intramedullary spinal cord tumors in children

Progressive spinal deformity after cervical intramedullary spinal cord tumor (IMSCT) resection requiring subsequent fusion occurs in many cases among pediatric patients. It remains unknown which subgroups of patients represent the greatest risk for progressive spinal deformity. The data for 58 patients undergoing surgical resection of cervical IMSCT at a single institution were retrospectively collected and analyzed for development of progressive spinal deformity requiring fusion. The association of all clinical, radiographic, and operative variables to subsequent progressive spinal deformity as a function of time was assessed via Kaplan-Meier plots and Log-rank and Cox analyses. Mean age at the time of surgery was 11 +/- 6 years. Eleven (19%) patients required subsequent fusion for progressive spinal deformity at a median [interquartile range (IQR)] of 4 (2-6) years after IMSCT resection. Five (36%) of 14 patients with preoperative scoliosis or loss of lordosis developed postoperative progressive spinal deformity compared to only 6 (13%) of 44 patients with normal preoperative sagittal and coronal balance, p = 0.06. Patients <13 years of age were more than three times more likely to develop postoperative progressive deformity, p = 0.05. Decompression spanning both the axial cervical spine (C1-C2) and the cervico-thoracic junction (C7-T1) increased the risk for progressive spinal deformity fourfold, p = 0.04. Number of spinal levels decompressed, revision surgery, radiotherapy, involvement of C1-C2 or C7-T1 alone in the decompression, or any other recorded variables were not associated with progressive postoperative spinal deformity. Patients possessing one or more of these characteristics should be monitored closely for progressive spinal deformity after surgery.

Myelopathy in a 6-year-old girl caused by neurofibromatosis Type 1: a case report

Background context Even when there is radiological evidence of spinal involvement, young patients with neurofibromatosis Type 1 (NF-1) seldom have symptoms. We report the case of a child who developed rapidly progressive myelopathy. Purpose To describe a technique used to prevent postoperative spinal deformity and instability, after removal of a dumbbell-shaped tumor in a 6-year-old child. Study design Case report. Patient sample A 6-year-old female. Methods Retrospective case review. Results The patient underwent a resection of the cervical dumbbell tumor using an osteoplastic laminectomy technique to prevent postoperative spinal deformity. At 2-year follow-up, there was no clinical or radiographic evidence of complications or spinal kyphotic deformity. Conclusions The case of a 6-year-old girl with cervical myelopathy caused by NF-1 was reported. The tumor was removed after osteoplastic laminectomy, which could prevent postoperative kyphotic deformity.

Spinal deformities following selective dorsal rhizotomy

Selective dorsal rhizotomy (SDR) has been shown to provide considerable benefit to children with spastic cerebral palsy (CP). The authors sought to evaluate the risks of postoperative spinal deformities in patients following SDR. All patients who underwent SDR at McGill University between 1991 and 2001 were identified. Hospital charts and radiographic spinal studies (both preoperative and the latest postoperative) were systematically reviewed. Univariate and multivariate regression analyses were conducted to test all independent variables of potential interest to determine risk factors more likely to be associated with spinal deformity. There were 98 patients whose mean age at surgery was 5.1 years; the mean radiographic follow-up duration was 5.8 years. Thirty-nine (44.8%) of 87 patients in whom postoperative weight-bearing radiographs were obtained had mild scoliosis, and 17 in whom standing radiographs were acquired had hyperlordosis. In all, 18 of 94 patients (19.1%) who had postoperative radiographs on which the lumbosacral junction was visible were found to have spondylolisthesis. Regression analysis identified the severity of preoperative CP as an important predictor, and less ambulatory patients were more likely to have scoliotic curves. Younger age at surgery and male sex were factors associated with a lower rate of hyperlordosis. Spondylolisthesis developed only in ambulatory children. None of the patients experienced clinically significant deficits. There was a high rate of radiologically documented deformities in patients with CP who underwent SDR. Ambulatory function, CP severity, age at surgery, and sex may be contributing factors.

Spinal deformity after multilevel osteoplastic laminotomy.

Multilevel laminectomy in children has a significant rate of postoperative spinal deformity. To decrease the incidence of this complication, the use of osteoplastic laminotomy is advocated to minimise the risk of spinal deformity by preserving the normal architecture of the spine. In this retrospective study, a 10-year series of a paediatric population undergoing multilevel osteoplastic laminotomy is reviewed to determine the incidence, especially in contrast to laminectomies, and to identify factors that affect the occurrence of spinal column deformity. Seventy patients (mean age 4.2 years) underwent multilevel osteoplastic laminotomy for congenital anomalies or removal of spinal tumours. All patients had a clinical and radiographic examination preoperatively, 12 months postoperatively and at follow-up. Mean follow-up was 5.3 years (range 3-12.6 years). Nineteen patients (27%) had a new or progressive spinal deformity. There was an increased incidence in patients who had surgery for spinal tumours (P<0.05), surgery of the cervical spine (<0.01), and who had more than five levels of the spine included (P<0.05). A review of the literature on children with multilevel laminectomy (n=330), the incidence of spinal deformity found a significantly higher (46%) compared to our study group. This study demonstrates that osteoplastic laminotomy was found to be very effective in decreasing the incidence of spinal deformities after spinal-canal surgery for spinal-cord tumours or congenital anomalies in children and adolescents. The choice of an anatomical reconstructive surgical technique such as osteoplastic laminotomy seems to be essential to minimise secondary problems due to the surgical technique itself. Nevertheless, growing patients should be followed up for several years after the initial operation for early detection and consequent management of any possible deformity of the spinal column.

Vertebral arch reconstruction based on 90 degree rotational laminoplasty after removal of spinal cord and cauda equina tumours.

A variety of procedures for reconstructing the spine following the removal of spinal cord and cauda equina tumours have been developed to prevent postoperative spinal deformities and nerve entrapment. The purpose of this paper is to introduce a new reconstructive procedure based on rotational laminoplasty and to report preliminary results in a small series. The trough is drilled at the border of the laminae and articular processes and the ligamentum flavum is resected on its cephalocaudal aspect, so the vertebral arch can be separated as a single mass. After tumour resection, the vertebral arch is removed en bloc with the laminae, and is rotated 90 degrees and placed on the articular facets and fixed using suture passing through holes drilled in the bone. One man and six women underwent rotational laminoplasty following resection of spinal or cauda equina tumours. Operative exposure was good and permitted complete resection. Patients did well postoperatively from both spine-surgical and neurosurgical points of view. Computed tomography documented a bony union with preservation of widely patent spinal canal. Rotational laminoplasty affords a satisfactory operative exposure for the resection of large, complex lesions. It creates a widely patent, stable spinal canal easily, without the need for special tools.

Intramedullary spinal cord tumors: Pediatric aspects and adjunct therapies

Intramedullary spinal cord tumors (IMSCTs) have specific clinical and pathological features in children. A long clinical course of erratic pains, scoliosis, or both is common. Unlike in adults, astrocytomas occur more frequently in children than ependymomas. A wide spectrum of histological types was observed in our series of 64 children 16-years-old or younger surgically treated for an IMSCT: 40 astrocytomas, 10 ependymomas, 3 gangliogliomas, 7 dysembryoplastic tumors, and 4 miscellaneous tumors. If surgical technique for removal of these tumors is the same as in adults patients and total removal can be achieved in 70 to 90% of the cases depending of the pathology, the approach to the spinal canal must be totally different. The laminotomy and closure must be meticulous, and postoperative immobilization with a brace is necessary. Applying these principles helps avoid postoperative spinal deformities. Long-term outcomes for benign tumors are encouraging. Follow-up without recurrences has been lengthy. The place of adjunct therapies must be defined for chemotherapy (CT), particularly for low-grade gliomas. Radiotherapy is contraindicated in children. New chemotherapeutic agents and new clinical trials are needed to improve the prognosis of malignant tumors.

服部式頚椎椎弓形成術と頚椎椎弓切除術の治療成績の比較検討

The purpose of this paper is to compare radiological changes after cervical laminoplasty and laminectomy. The subjects were 78 patients with myelopathy caused by the cervical spondylosis or the ossification of the posterior longitudinal ligament in the cervical spine. 61 cases were treated using Z-shaped laminoplasty (Hattori's Method) and 16 using laminectomy. The average age at the time of surgery was 57, and the average follow-up period was 11 years and 2 months. The functional results were evaluated according to the Japanese Orthopaedic Association's scoring system. At the time of follow-up, the average recovery rate was 63% in the laminoplasty group, and 32% in the laminectomy group. In the laminoplasty group, the abnormality of alignment was greatly reduced in frequency and degree compared with the laminectomy group. The recovery rate was poor in patients with postoperative changes in the type of cervical spine curvature developed. Laminoplasty is considered to be superior to laminectomy in maintaining cervical alignment and preventing postoperative spinal deformities.

家兎における服部式頚椎椎弓形成術および椎弓切除術の術後頚椎支持性に関する検討

The purpose of this paper is to evaluate the radiographical differences and biomechanical responses of laminectomy and laminoplasty in animal models. Twenty-three Japanese white rabbits were divided into 2 groups, one undergoing C3-C7 laminectomy and the other Z-shaped laminoplasty (Hattori's Method). Lateral cervical spine radiographs were obtained pre-operatively and 2, 4, and 12 weeks post-operatively, and biomechanical testing was performed after the rabbits were put to sleep. Laminoplasty was considerably reduced the frequency the postoperative alignment abnormality compared with laminectomy. The biomechanical results showed that the flexion stiffness at 20 degree for the laminectomy group was lower than for the intact and laminoplasty groups after the procedure. Radiographical and biomechanical of the rabbit models suggest that laminoplasty is more effective than laminectomy in maintaining cervical alignment and preventing postoperative spinal deformities.

Spinal deformity and instability after multilevel cervical laminectomy for spondylotic myelopathy.

A retrospective radiographic and medical record analysis of 58 patients. To describe the incidence and consequences of cervical spinal deformity and instability after multilevel laminectomy in adult patients with myelopathy caused by cervical spondylosis and to determine the usefulness of preoperative dynamic roentgenographic films in the prevention of postoperative destabilization. Extensive cervical laminectomy has been widely used in the treatment of progressive myelopathy secondary to stenotic conditions. Complications of this procedure, including spinal instability, accelerated spondylotic changes, postoperative spinal deformity, and constriction of the dura mater by formation of extradural scar tissue formation have been recognized. However, the frequency of these complications is probably overestimated, and their effect on clinical outcome remains unknown. Fifty-eight patients older than 30 years who underwent a laminectomy at more than three levels without fusion for myelopathy secondary to cervical spondylosis were reviewed retrospectively with an average follow-up of 3.6 years. Functional results were evaluated according to the Japanese Orthopaedic Association's scoring system. Lateral views in neutral position, in flexion, and in extension of the preoperative cervical roentgenograms were analyzed in comparison with the last follow-up films to identify the changes in the curvature of the cervical column, in the range of motion of the neck, and in the intervertebral angular mobility and anteroposterior displacement of the vertebral bodies and finally to quantify the incidence of spinal instability. In 18 patients (31%), postoperative changes in the type of cervical spine curvature developed. Fifteen patients (25%) had destabilization at one or more levels. Deformities of the cervical spine occurring after surgery do not appear to cause symptoms or neurologic abnormalities. Destabilization required repeat surgery in 3 patients. All the levels appearing to be destabilized on the postoperative films were hypermobile on the preoperative dynamic radiographs. Preoperative olisthesis Without hypermobility is not a factor of risk in postoperative destabilization. The use of preoperative dynamic radiographs should improve the selection of patients undergoing laminectomy for the treatment of multilevel cervical cord compression. Dynamic radiographs may also reinforce the need for such adjunctive procedures as fusion and instrumentation, to prevent postoperative destabilization. Preoperative olisthesis with hypermobility in sagittal or horizontal planes must be fused and instrumented.

Spinal column deformity and instability after lumbar or thoracolumbar laminectomy for intraspinal tumors in children and young adults.

A retrospective study about the occurrence of spinal column deformity or instability after multilevel lumbar or thoracolumbar total laminectomy for removal of benign intraspinal tumors in children and young adults. To analyze the long-term clinical and radiographic outcome of these patients, and to specify factors that affect the occurrence of postlaminectomy spinal column deformity and instability. Spinal column deformity is not uncommon after multilevel cervical or thoracic laminectomies for removal of intraspinal tumors in children. Its incidence in the lumbar and thoracolumbar spine reportedly is low. Thirty-six consecutive patients (23 male, 13 female) underwent multilevel lumbar or thoracolumbar total laminectomy for removal of benign intraspinal tumors from 1966 to 1989. Twelve patients were aged 17 years or younger ("children and adolescents"; mean age, 11 years), and 24 were aged 18-30 years ("young adults"; mean age, 24 years). All patients had preoperative, immediate postoperative, and follow-up clinical and radiographic examinations. At a mean follow-up period of 14 years (range, 4-28 years), six patients (16.6%) had spinal deformity (lordosis or thoracolumbar kyphosis associated with scoliosis), and four (11%) had spondylolisthesis. Spinal column deformity occurred in 33% of children and adolescents and in 8% of young adults. Spondylolisthesis occurred in 16.6% of children and adolescents and in 8% of young adults. Three patients had fusion for spinal column deformity. Pain was present in eight patients, and other neurologic signs and symptoms were found in 18. There was an increased incidence of postoperative spinal deformity in patients who had more than two laminae removed (P < 0.01) or a facetectomy performed at the time of the initial operation (P < 0.05). There was no association between the occurrence of the deformity and sex, neurologic condition after laminectomy, or length of follow-up period. Spinal deformity or instability after multilevel lumbar or thoracolumbar total laminectomy is not uncommon in children and adolescents. Limiting laminae removal and facet destruction may decrease this incidence. Fusion may be required to correct post-laminectomy deformity and to stabilize the spine.

Dynamics of the spinal cord: an analysis of functional myelography by CT scan.

The antero-posterior movement of the spinal cord with flexion and extension of the neck was analyzed in order to clarify the mechanism of spinal cord compression in cases with postoperative spinal deformity, and to contribute to the improvement of the surgical methods of conventional laminectomy. The control subjects were 47 cases without cervico-thoracic neurological symptoms, who underwent CT myelography in flexion and extension of the neck; the cervical spinal cord was examined in 27 of these cases and the thoracic cord in the other 20. CT myelography was also carried out in 16 patients with cervical myelopathy and in 5 patients after posterior decompression surgery (suspension laminotomy). CT sections in flexion and extension of the neck were analyzed for 1) change of configuration of the dura mater and the spinal cord, and 2) antero-posterior shift of the spinal cord in the subarachnoid space. In the control subjects, the configuration of the dura mater was slightly flattened at C5/6, C6 and C6/7 in extension of the neck. The cervical spinal cord shifted anteriorly in flexion and posteriorly in extension of the neck, and was flattened at the midcervical level in flexion in the control subjects. There was a statistically significant correlation between the location of the spinal cord and the adjacent intervertebral angles at the levels of C4, C5 and C6. These results were compared with the results from the 16 patients with cervical myelopathy and 5 patients after suspension laminotomy.(ABSTRACT TRUNCATED AT 250 WORDS)

Suspension laminotomy: a new surgical technique for compression myelopathy.

In an attempt to eliminate the many negative aspects of conventional extensive laminectomy, we originated in 1981 and have developed a new surgical technique called "suspension laminotomy." A basic principle of this operation is preservation and repair of the soft and bony tissue of the spine with osseous enlargement of the spinal canal. Eighty-one patients were treated with suspension laminotomy. This operative technique can be applied to almost all segments of the spine and can be used for all cases that would usually have been treated with conventional extensive laminectomy. We emphasize the necessity of repairing paraspinal muscles and discuss the postoperative spinal deformities and the dural constriction, which seemed to be caused by scar formation after conventional laminectomy. Suspension laminotomy should minimize the negative aspects of conventional extensive laminectomy.