The neurologic deficit associated with lipomas of the cauda equina

Congenital Spinal Lipomatous Malformations. Part 1. Spinal Lipomas, Lipomyeloceles, and Lipomyelomeningoceles

Background: Lumbosacral spinal lipomas and lipomyeloceles are usually identified in early childhood. Terminology, histopathology, and diagnosis for these malformations can be confusing. Materials and Methods: This is a PubMed review with comparison of embryology, gross, and histopathology, and reporting requisites for these and related closed spinal malformations. Results: The spinal lipoma group (congenital spinal lipomatous malformations) includes subcutaneous, transdural, intradural, and noncontiguous malformations stretching through the entire lower spinal region. This lipomyelocele trajectory overlaps the embryonic tail's caudal eminence. Histopathologically, the lipomyelocele spectrum is a heterogeneous, stereotypical set of findings encountered from dermis to spinal cord. Diagnosis requires detailed correlation of images, intraoperative inspection, and histopathology. Conclusions: Appropriate terminology and clinicopathologic correlation to arrive at a diagnosis is a critical activity shared by pathologist and clinician. Prognostic and management differences depend on specific diagnoses. Familial and genetic influences play little if any role in patient management in closed spinal malformations.

History of the current understanding and management of tethered spinal cord

An understanding of the underlying pathophysiology of tethered cord syndrome (TCS) and modern management strategies have only developed within the past few decades. Current understanding of this entity first began with the understanding and management of spina bifida; this later led to the gradual recognition of spina bifida occulta and the symptoms associated with tethering of the filum terminale. In the 17th century, Dutch anatomists provided the first descriptions and initiated surgical management efforts for spina bifida. In the 19th century, the term “spina bifida occulta” was coined and various presentations of spinal dysraphism were appreciated. The association of urinary, cutaneous, and skeletal abnormalities with spinal dysraphism was recognized in the 20th century. Early in the 20th century, some physicians began to suspect that traction on the conus medullaris caused myelodysplasia-related symptoms and that prophylactic surgical management could prevent the occurrence of clinical manifestations. It was not, however, until later in the 20th century that the term “tethered spinal cord” and the modern management of TCS were introduced. This gradual advancement in understanding at a time before the development of modern imaging modalities illustrates how, over the centuries, anatomists, pathologists, neurologists, and surgeons used clinical examination, a high level of suspicion, and interest in the subtle and overt clinical appearances of spinal dysraphism and TCS to advance understanding of pathophysiology, clinical appearance, and treatment of this entity. With the availability of modern imaging, spinal dysraphism can now be diagnosed and treated as early as the intrauterine stage.

Surgical treatment for lipomyelomeningocele in children

BACKGROUND

Lipomyelomeningocele (LMM) is a common and severe closed neural tube defect in children. Because of the complex anatomy of LMM and the difficulty in assessing the value of surgery, the management of patients with LMM is controversial. This study was undertaken to evaluate effective techniques and procedures in surgical treatment of LMM and to assess the value of early neurosurgical intervention.

METHODS

Twenty-five children with LMM aged from 2 months to 6 years underwent surgery between January 2004 and December 2006. Magnetic resonance imaging (MRI) of the spine and electromyography (EMG) of the lower limbs was conducted in all patients preoperatively. Urodynamic studies were appropriate even in asymptomatic patients. Hoffman's functional grading was used to assess the pre and postoperative status of the patients. The operation was composed of subtotal excision of lipoma, suturing of the spinal pia mater, and section of the filum terminale. Suturing of the spinal pia mater was performed in a wide process of reconstruction of meningeal layers including the dura. Follow-up lasted 1-4 years (mean 2.1 years), in which all children underwent neurological examination, EMG and MRI.

RESULTS

After surgery a temporary neurological deterioration was found in two patients including slight weakness of a leg in one patient and urinary retention in the other, but it recovered completely a few days later. No postoperative complications were encountered. During the follow-up, 20 asymptomatic patients remained symptom-free. Symptoms disappeared totally in 2 of the 5 patients with neurological deficits, improved in one patient and stabilized in the remaining 2. MRI showed no tethered cord in all patients who underwent surgical procedures.

CONCLUSIONS

Early operation for LMM patients, even asymptomatic ones, should be performed to prevent the development of neurological deficits. Subtotal excision of lipoma, suturing of the spinal pia mater, and section of the filum terminale are recommended in the surgical treatment of LMM. The longitudinal cut of the filum terminale, a technique we have established in our surgical practice, is a simple and practical way to identify the filum terminale by visual inspection. And suturing the spinal pia mater is of extreme importance in preventing postoperative tethering.

Lumbar lipomyelomeningocele and sacrococcygeal teratoma in siblings: support for an alternative theory of spinal teratoma formation

Sacrococcygeal teratomas may arise in association with regional developmental errors affecting the caudal embryonic segments and may originate within lumbosacral lipomas. It is therefore possible that sacrococcygeal teratomas and lumbosacral lipomas represent related disorders of embryogenesis. Accordingly, the authors report the cases of 2 siblings. The first child (female) was born with a mature Altman Type III sacrococcygeal teratoma that was resected when she was a neonate. Subsequently, a younger brother was found soon after birth to have an L-4-level lipomyelomeningocele and underwent partial resection and spinal cord untethering at 4 months of age. Although familial forms of each of these conditions have been reported, this is, to the authors' knowledge, the first reported occurrence of lipomyelomeningocele and sacrococcygeal teratoma in siblings. They propose that an inherited regional tendency to developmental error affecting the caudal embryonic segments was shared by these siblings and resulted in spinal teratoma formation in one of them.

Congenital spinal lipomatous malformations: part I--Classification

BACKGROUND

Congenital spinal lipomatous malformations constitute a diverse group of lesions. There is considerable confusion in the literature regarding their terminology and a proper classification is long overdue. The first part of this two part report sets out a proposed classification scheme.

METHODS

On the basis of this author's experience with 80 patients with a congenital spinal lipomatous malformation treated over a 10 year period, a new classification is proposed. The proposed classification divides congenital spinal lipomatous malformations into two broad groups: 1. Lipomas without dural defect and, 2. Lipomas with dural defect. Within each group, there are several subtypes. These two broad groups differ from one another in their embryology, clinical presentation, operative findings, complications and prognosis

FINDINGS

Group I consists of Lipomas without dural defect. Included in this group are: Filum lipoma, caudal lipoma without dural defect, and intramedullary lipoma. Group II consists of lipomas with dural defect. Included in this group are: dorsal lipoma, caudal lipoma with dural defect, transitional lipoma, lipomyelocele, and lipomyelomeningocele. The definitions of the various subtypes and radiological and operative findings of all these lesions are described.

CONCLUSIONS

Congenital spinal lipomatous malformations constitute a wide spectrum of lesions ranging from relatively simple lipomas of the filum terminale to complex malformations. These lesions differ from one another in their embryology, clinical presentation, operative strategies, complications and prognosis. Failure to differentiate between the different forms of congenital spinal lipomatous malformations may lead to inaccurate assumptions regarding prognosis and inappropriate management. The proposed classification seeks to address these issues.

Cord untethering for lipomyelomeningocele: expectation after surgery

✓Tethering of the conus medullaris is assumed to be the primary cause of the deterioration seen in children with transitional lipomyelomeningocele (LMMC). The inevitability of deterioration has led to the use of prophylactic interventions to stabilize or prevent further clinical deterioration. The author reviewed current literature to define the timing and pattern of deterioration prior to and following initial cord untethering in patients with transitional LMMC, as well as the operative burden that these children bear in exchange for optimized function.

Intraoperative mapping of sacral nervous system (S2-4)

Electrophysiological mapping of the sacral nervous system was used during operations on 80 patients with conus and cauda equina lesions. At surgery, under controlled muscle relaxation, the sacral neural elements (S2-4) were mapped using direct mono-polar stimulation and recording of compound muscle action potentials (CMAPs) from the external anal sphincter (EAS). Responses were obtained in 86.25% (69/80) of the patients. In 33 (82.5%) out of 40 patients with preoperative deficits involving the S2-4 segments, CMAPs could be elicited. Identification of nerve roots was useful in dissection of lipomyelomeningocoeles, tumour excisions and untethering of filum terminale. In three patients, stimulation of the filum terminale elicited motor responses and, hence, it was not sectioned. Intraoperative mapping of the S2-4 nerve roots under controlled muscle relaxation is feasible in a majority of patients, including those with deficits involving S2-4. This method was useful in sparing viable nerve roots during surgery in conus and cauda equina regions, and identification of 'functional' filum terminale.

Adult onset tethered cord syndrome associated with intradural dermoid cyst. A case report

STUDY DESIGN

A case report and a review of literature.

OBJECTIVES

To describe a rare case of adult onset tethered cord syndrome associated with intradural dermoid cyst.

SETTING

General Orthopedics, Japan.

METHODS

A 50-year-old woman was referred to us because of right leg pain and pollakiuria. Neurological examinations and radiological assessments including myelography, computerized tomography scan and Magnetic resonance image were carried out. We diagnosed it as the adult onset tethered cord syndrome associated with an intradural cystic lesion.

RESULTS

The cystic lesion was totally removed following laminectomy from L5 through S4. Histologically, the tumor was diagnosed as a dermoid cyst.

CONCLUSIONS

Intradural dermoid could produce adult onset tethered cord syndrome, but it was not reported in the English literatures to our knowledge.

Neurological manifestation of sacral tumors

An extensive analysis of the existing literature concerning sacral tumors was conducted to characterize their clinical manifestations. Although certain specific manifestations can be attributed to some of the tumor types, a more general pattern of clinical presentation of an expansive sacral lesion can be elaborated. Local pain with or without pseudoradicular or radicular radiation is the most frequent initial symptom and is usually followed by the manifestation of a lumbosacral sensorimotor deficit; bladder/bowel and/or sexual dysfunction appear throughout the natural course of disease.

Prenatal sonographic detection of a lipomeningocele as a sacral lesion

We present a case of a lipomeningocele in a newborn. Prenatal sonography revealed dysraphia and a 3.8 x 4.3 cm, semisolid, echogenic mass that was continuous with the sacral area and bulged posteriorly under the skin. The mass was diagnosed after birth as a lipomeningocele based on the results of MRI. This diagnosis was confirmed histologically.

Congenital intraspinal lipomas: histological analysis of 234 cases and review of the literature

The clinical, radiologic, and pathologic data from a series of 234 patients hospitalized in the Pediatric Neurosurgical Department of the Necker-Enfants Malades Hospital, Paris, for congenital intraspinal lipomas and operated on from 1976 to 1995 were examined. Histological studies showed that these lesions may be simple lipomas, similar to those developing elsewhere in the body, or they may be more complex forms including in addition to the lipomatous component a variety of unusual ectopic tissues of ectodermal, mesodermal, and/or endodermal origin. These complex forms indica te the malformative nature of these tumors. When they contain elements that are truly foreign to the region, the possibility of teratoma with a tumoral potential should be considered. Data found in the literature and from Necker-Enfants Malades Hospital are discussed.

The tethered spinal cord: diagnosis, significance, and management

Tethered cord is the result of fixation of the spinal cord, which limits motion in the caudal-rostral direction. Most children either have cutaneous markers or a predisposing condition. Prophylactic release of the spinal cord can prevent the long-term disabilities associated with this condition. Although delayed release, following the onset of a neurological deficit, may reverse some lost function, it is unlikely to restore bladder and bowel function.

Spina bifida and intraspinal lipomas

Experience with nine consecutive cases of intraspinal lipomas revealed some unreported observations. The results of surgery are discussed with regard to pathology, timing of surgery and a modified surgical technique. Earlier compared to later operative intervention produces less bleeding, shorter operation time, easier removal of softer lipoma and easier reconstruction of conus and cord after removal of mass. Adequate dura cover can always be obtained by stripping off the dura from the fibro fatty stalk of lumbosacral lipoma. Watertight closure of dura prevents cerebrospinal fluid (CSF) leak and is ensured by the use of continuous monofilament suture material such as prolene.

Bladder functional changes resulting from lipomyelomeningocele repair

From 1986 to 1991, 12 boys and 23 girls underwent surgery for lipomyelomeningocele removal. Of these patients 29 were 15 months old or younger (average age 3 months), while 6 were 4.5 to 19 years old (average age 10 years). Preoperative and postoperative urodynamic studies, including external urethral sphincter electromyography, were done on everyone. All 29 infants had a cutaneous lesion overlying the lower back and 14 had an abnormal neurological examination. Preoperative urodynamic studies were abnormal in 11 patients, consisting of an upper motor neuron lesion in 6, and a mixed upper and lower motor neuron lesion in 5. Postoperatively, 10 of 14 children with an abnormal neurological examination improved, while 9 of 11 with abnormal lower urinary tract function normalized. In 1 of 18 children (6%) with normal preoperative urodynamic studies detrusor-sphincter dyssynergia developed postoperatively. In all 6 older children urinary incontinence developed, and this led to the diagnosis. Everyone had an abnormal neurological examination and abnormal preoperative urodynamic studies. One child had a lower motor neuron lesion, and 5 had a mixed upper and lower motor neuron lesion. Postoperatively, the neurological examination improved in only 1 patient (16%), and the urological symptoms and urodynamic findings improved in another child. Lipomyelomeningocele has a progressive effect on lower spinal cord function because infants tend to present with fewer urinary manifestations and physical findings than older children. Individuals who escape early detection tend to have a more subtle cutaneous abnormality. As a result, older children are more likely to present with urological and neurological complaints. Surgical correction in infancy provides a degree of reversibility not seen in older children. It is imperative that early identification, evaluation and treatment be undertaken to prevent this progression and permanency of neurological changes and urinary dysfunction.

Electrical stimulation and multichannel EMG recording for identification of functional neural tissue during cauda equina surgery

Electrical stimulation of structures within the surgical field was used to identify functional neural elements during 25 cauda equina operations. EMG responses from anterior thigh, posterior thigh, and anal sphincter muscles were recorded simultaneously using a multichannel signal averager. During nine operations, stimulation of a presumed filum terminale or other tissue produced clear EMG responses, prompting modification of surgical procedures. In one patient, this resulted in preservation of a flattened spinal cord which resembled a band of scar tissue. Some EMG responses were restricted to a single muscle group; these neural structures would probably not have been identified if only a single-channel EMG recording was used. Visual examination alone was not adequate for identifying functional neural elements, or for determining whether atretic-appearing nerve roots were functional. Electrical stimulation with multichannel EMG recording facilitates the preservation of functional neural elements and the optimization of surgical results in cauda equina surgery.

Long term follow up of patients with cauda equina syndrome due to intraspinal lipoma

We have had the opportunity to treat and follow up two young males with cauda equina syndromes after recurrent resection of intraspinal lipomas. This condition is relatively rare. The patients underwent myelographies, operations, long periods of hospitalisation, and rehabilitation. The syndromes included low back pain, arachnoiditis, and recurrence of the lipoma after several years and multiple operations. These are the problems that we were faced with: (1) Although the tumor is benign it is impossible to resect it completely. (2) There are complications which interfere with rehabilitation, including pain, arachnoiditis, and neurological deterioration. (3) Long term prognosis might be grave and the patient and family should know this. (4) Physiotherapy and sports: should these patients perform strenuous exercise or not?

Occult spinal dysraphism in children: need for early neurosurgical referral

The natural history of occult spinal dysraphism in children is one of progressive and unpredictable neurological deficit. The modern role of neurosurgery is in the prevention of deterioration rather than correction of established disability. A prospective study was carried out on 40 consecutive patients to analyse the referral pattern of children with this condition. The age, reason for referral, clinical history and source of referral was recorded in each case. The reason for referral varied with age. Of the 40 patients studied, only 12 were found to be without neurological deficit at the time of referral. The incidence of progressive neurological deterioration increased with increasing age. The referral source in different age groups varied, but in all age groups relatively few were referred by the general paediatricians or paediatric neurologists. For optimum surgical results, early referral and treatment is desirable and should become our objective.

Leptomyelolipoma: analysis of 20 cases

Leptomyelolipoma (lumbosacral lipoma) is a common form of spinal dysraphism. The deficits produced include sensory, motor, bowel, and bladder dysfunction, and vary in incidence between the pediatric and adult populations. Twenty patients treated surgically at the Mount Sinai Hospital between 1972 and 1988 are reviewed. Fifty percent were 12 years of age or less and 50% were older than 18 years of age. The surgical approach was designed to accomplish untethering of the conus medullaris, debulking of the lipomatous mass compressing the cord, reconstruction of the dural canal, and reapproximation of the paraspinal muscles and lumbosacral fascia to prevent future trauma. Postoperatively, no patient experienced deterioration of neurological function. Of the symptomatic patients. 67% displayed dramatic improvement or became asymptomatic and 33% experienced stabilization of their deficits. The symptoms most resistant to surgical correction were orthopedic foot deformities and bowel dysfunction, whereas bladder dysfunction, motor weakness, and radiculopathies were most amenable to surgical therapy. Early surgical repair is recommended in these cases to forestall irreversible neurological damage.

Tethered cord syndrome versus low-placed conus medullaris in an over-distended spinal cord following initial repair for myelodysplasia

We present findings obtained from a total of 100 patients who had previously undergone surgery for spina bifida and whose progress had been monitored by magnetic resonance imaging (MRI) in our meningomyelocele clinic. Fourteen of these patients (14.0%) developed delayed symptom(s) of progressive spinal neurologic dysfunction. In those with myeloschisis, increase of motor deficit was the most common clinical manifestation during infancy and early childhood (mean age: 6.8 years), whereas pain on back flexion was seen in patients who were over 15 years of age (mean age: 17.3 years). MRI carried out in myeloschisis patients invariably demonstrated that the conus medullaris was in an abnormally low position, suggesting over-distension of the spinal cord. This was irrespective of whether symptom(s) developed or not and did not correlate with the initial surgical procedure (reconstructive or otherwise) used. Patients with symptom(s) were revealed by MRI to have an extremely low conus set at the spinal level of S-1 or below; neurological examinations showed that the motor deficit occurred at high levels in the spine. Results from lipomeningocele patients were more erratic in terms of conus position and delayed development of neurological defects.(ABSTRACT TRUNCATED AT 250 WORDS)

Bladder function in patients with lipomyelomeningocele

We evaluated preoperative and postoperative bladder function in 31 consecutive patients who underwent definitive operative correction of lipomyelomeningocele. Of 12 patients less than 1.5 years old at operation, bladder function was normal preoperatively and postoperatively in 5 (42%) and normalized postoperatively in 4 (33%). In 5 patients (42%) abnormal urodynamic findings were the only sign of neurological abnormality. Of the 19 patients older than 1.5 years at operation bladder function was normal preoperatively and postoperatively in only 4 (21%), and normalized postoperatively in none. We conclude that the majority of patients with lipomyelomeningocele have bladder dysfunction, and that in some cases this dysfunction can be prevented and/or reversed by early neurosurgical intervention. Urodynamic assessment is helpful as part of the neurological evaluation and in directing patient care.

Electrophysiological monitoring during lipomyelomeningocele resection

Surgical resection of a lipomyelomeningocele carries a risk of injury to nerve roots in the cauda equina. We have devised a technique for combined spinal evoked potential and peripheral nerve compound action potential recording for intraoperative monitoring of this surgical procedure. We report the results of six cases where this technique was used. In each case, the monitoring prevented resection of viable neural tissue, and all six patients were neurologically unchanged postoperatively.

Lumbosacral lipomas with spina bifida

The pathological and metabolic characteristics, as well as the anatomical and functional evolution of lumbosacral lipomas, were studied in a series of 73 patients operated on between 1970 and 1983. The pathological study showed that they are mainly composed of adipocytes, but that they also possess fibrous tissue, vessels, and nerve fibers. Innervated muscle fibers, contracting under proper nerve stimulation, were found in several cases. Lipogenesis and lipolysis are the same in lumbosacral lipomas and in normal fat tissue. However, these lipomas can grow with the rest of the fatty pool. Moreover, spontaneous progressive worsening of the clinical status has been observed in 36% of the cases. Surgery is efficient and not harmful to the patient. Postoperative mortality was nil. Early postoperative worsening occurred in 2.7% of the cases. The 6% rate of late postsurgical deteriorations should be compared to the 36% to 56% rate found when patients are not operated on. Three different mechanisms are responsible for clinical worsening: compression or stretching of the cord, and cord injury on the posterior upper limit of the spinal defect. In each case, one mechanism is prevalent. Three different types of lumbosacral lipomas can thus be individualized. The surgical implications of these data are discussed. The necessity for early and systematic surgical treatment is pointed out.

Magnetic resonance imaging: lumbosacral lipoma

To evaluate the clinical efficacy of magnetic resonance imaging (MRI) of lumbosacral lipomas, the magnetic resonance images of nine patients were reviewed. T1- and T2-weighted spin echo sequences were used with a 0.5-T magnetic resonance system. The tethered or low-positioned conus medullaris, the lipoma itself, the lipoma--cord interface, the subarachnoid space, and hydromyelia were clearly disclosed. The nerve rootlets were not as clear. These results indicate the possible discontinuance of myelography and metrizamide computed tomography (CT) cisternography for such imaging. The diagnostic modalities of choice for lumbosacral lipoma imaging are plain spine films, plain CT scan, and MRI.

Congenital lumbosacral lipoma causing primary enuresis in an adult

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Occult spinal dysraphism. Case report and review of the literature

This case report and review of the literature is presented to create a greater diagnostic awareness of occult spinal dysraphism. Early recognition is based upon an understanding of this congenital anomaly and its variable presentations. These most commonly include abnormal gait, various cutaneous manifestations, particularly subcutaneous lipomata, and less frequently urological complaints. Surgical intervention, to arrest disease progression, is the primary mode of treatment, and functional improvement is variable. Long-term prognosis is dependent upon severity of neurologic deficits prior to surgery and the type of lesion found intraoperatively. Familial occurrence has been reported and genetic counseling may be an important preventive measure. Recent radiologic investigations have been concerned with the use of ultrasonography in screening infants at risk.

Are the metabolic characteristics of congenital intraspinal lipoma cells identical to, or different from normal adipocytes?

Congenital intraspinal lipomas are frequently responsible for progressive neurological deficits caused by distortion or compression of the nervous system. Since fat metabolism in these lesions has not been previously studied, the aim of this study was to determine whether intraspinal lipoma cells behave like lipomas or like normal adipocytes. In 11 patients, intraspinal lipoma cells were compared with normal adipocytes isolated from adjacent subcutaneous adipose tissue for the following parameters: lipoprotein lipase (LPL), lipogenesis from U14C glucose, beta-receptor number, adenylate cyclase activity, cyclic AMP production, and lipolysis in response to beta- and alpha 2-adrenergic agonists. No significant difference between these two cell populations was found, suggesting that intraspinal lipomas are not lipomatous tumors, but hamartomatous lesions capable of growth and regression along with the changes in the rest of the fatty pool. This emphasizes the danger of an abnormal weight gain, as well as the possible usefulness of an hypocaloric diet in patients who worsen in spite of previous surgery.

Surgically confirmed myelographic classification of congenital intraspinal lipoma in the lumbosacral region

Twenty-four cases of histologically confirmed congenital intraspinal lipoma of the lumbosacral region were studied by means of myelography with metrizamide. The findings were compared with intraoperative observations. Myelography with metrizamide clearly revealed the detailed intrathecal structures and allowed a classification of intraspinal lipomas into four types, in terms of their insertion into the conus medullaris: dorsal type, either with direct or indirect (via an intrathecal stalk) insertion of the extrathecal lipoma into the dorsal aspect of the conus medullaris; caudal type; combined type; and filar lipoma. Based on our surgical experience in untethering and decompression of the lesions, the classification was found to be useful in designing a safe and effective surgical procedure which minimized all possible trauma to the intrathecal neural structures.

Management of lipomyelomeningoceles. Experience at the Hospital for Sick Children, Toronto

Ninety-seven children with lipomyelomeningoceles were operated on at the Hospital for Sick Children between January, 1960, and December, 1982. The most common factor that caused these patients to seek help was the cosmetic effect of the mass on their back. However, 22 patients had urinary incontinence and 15 patients had a deformed or weak leg. Sixty of the 97 patients were female and 37 were male. The patients presented for treatment between 6 days and 18 1/2 years of age with a median age of 7 1/2 months. Fifty-six patients presented before the age of 6 months and 35 of these were perfectly normal at the time of presentation. On the other hand, of the 41 patients who were brought for treatment after the age of 6 months, only 12 were normal prior to surgery. When patients were appropriately treated at an early age, with their spinal cords untethered and their dura securely closed with a dural graft, then they remained unchanged neurologically or even improved. However, when treatment was delayed or not done appropriately then they were left with significant neurological sequelae. Lipomyelomeningoceles are serious lesions which without appropriate therapy can result in gross impairment of neurological function.

Spinal dysraphia and elongated spinal cord in adults

Spinal dysraphia with stretching of the spinal cord is usually diagnosed in the adolescent or young-adult patient. Two types of the condition are distinguished: a stretched spinal cord with an intradural lipoma, and a stretched spinal cord with both an intra- and extradural lipoma. The pathogenesis of the condition and mechanical role of the lipoma and the late appearing neurological signs are presented.

Tethered cord syndrome in adults

Patients with tethered cord syndrome (TCS) rarely have symptomatic onset in adulthood. Twenty-three adult patients with TCS were studied with respect to the clinical, radiological, and pathological features of this syndrome. Specific circumstances involving either additional tugging of the already tight conus, narrowing of the spinal canal, or direct trauma to the back or buttocks precipitated symptomatic onset in 60% of patients. Diffuse and non-dermatomal leg pain, often referred to the anorectal region, was the most common presenting symptom. Progressive sensorimotor deficits in the lower extremities as well as bladder and bowel dysfunction were also common findings; but, unlike TCS in children, progressive foot and spinal deformities were not seen. As in TCS with onset in childhood, the most common tethering lesions were thickened filum, intradural lipoma, and fibrous adhesions. The degree of cord traction, rather than the type or distribution of the tethering lesions, probably determines the age of symptom onset: less severe traction remains asymptomatic in childhood but results in neurological dysfunction in later life due to repeated tugging of the conus during natural head and neck flexion, or when abnormal tension is aggravated by trauma or spondylotic canal stenosis. Metrizamide myelography revealed the diagnosis of tethered conus in most cases, but the addition of computerized tomographic imaging provided valuable structural details concerning the tethering lesion. The surgical outcome was gratifying in relation to pain and motor weakness but disappointing in the resolution of bowel and bladder dysfunction. Early diagnosis and adequate release of the tethered conus are the keys to successful management.

Pathophysiology of "tethered cord syndrome"

The tethered cord syndrome is a clinical entity manifested by progressive motor and sensory changes in the legs, incontinence, back of leg pain, and scoliosis. In order to elucidate the pathophysiology involved in the tethered cord, the reduction/oxidation ratio (redox) was used in vivo of cytochrome alpha,alpha 3 to signal oxidative metabolic functioning in human examples of tethered cord and in animal models. Studies in experimental models indicate marked metabolic and electrophysiological susceptibility to hypoxic stress to lumbosacral cord under traction with greater weights (3, 4 or 5 gm). Similar effects were demonstrated in redox behavior of human tethered cord during surgical procedures. The authors conclude that symptoms and signs of tethered cord are concomitant with lumbosacral neuronal dysfunction which could be due to impairment of mitochondrial oxidative metabolism under constant or intermittent cord stretching. It is assumed that prolonged or accentuated neuronal dysfunction may lead to structural damage to the neuronal perikarya and later of the axons. Untethering procedures in human tethered cord improve oxidative metabolism, and probably facilitate the repair mechanism of injured neurons.