Pathophysiology of tethered cord syndrome and similar complex disorders.

Tethered cord syndrome (TCS) is a stretch-induced functional disorder of the spinal cord due to the fact that its caudal portion is anchored by an inelastic structure. The functional lesion of TCS is generally situated in the lumbosacral cord, and many authors have shown that the syndrome is reversible via surgery to untether the cord. To clarify the expressions relevant to TCS, such as "cord tethering" and "tethered cord," the authors have formulated three categories. These categories include cases that show the anatomical appearance of spinal cord stretching. Among them, Category 1 is isolated to represent the "true TCS." The authors focus their discussion of the pathophysiology of TCS on Category 1 to explain the impaired oxidative metabolism and electrophysiological derangements within the tethered spinal cord, which is the primary intrinsic cause of the dysfunction. Furthermore, they extend the discussion to the extrinsic (outside the spinal cord) factors and other complex conditions that mimic TCS.

A novel, simplified pediatric syringopleural shunt. Technical note.

The diversion of fluid from an intramedullary syrinx cavity is an option for the treatment of syringomyelia. The authors have modified the technique of shunting syrinx fluid to the pleural space with the aid of a simple short tube and a single incision; this is a one-stage operation in pediatric patients. The advantages of this technique include the use of familiar standard neurosurgical techniques, the availability of shunt components, a short, direct catheter course, the minimization of a siphoning effect secondary to improved catheter tip placement, and the use of pleural rather than peritoneal space. In this small series the technique of syringopleural shunting has proved simple, safe, and well tolerated by pediatric patients.

Tethered cord syndrome: overview of diagnosis and treatment.

This article covers the basis of tethered cord syndrome as a stretch-induced spinal cord disorder, including pathophysiology, signs and symptoms, imaging diagnosis, indication for surgical treatment, and surgical procedures. Anomalies that cause mechanical spinal cord tethering are listed, and the surgical untethering technique for each anomaly is described.

Adult tethered cord syndrome: relative to spinal cord length and filum thickness.

The adults with tethered cord syndrome (TCS) are divided into two groups: group-1 adult TCS patients with spinal dysraphism; and group-2 patients without dysraphism who develop signs and symptoms in adulthood. A significant number of group-2 patients failed to show elongation of the spinal cord and abnormally thick filum terminale. This paper reports the combinations of the location of the caudal end of the spinal cord and the thickness of the filum terminale in 104 patients with group-2 adult TCS. The caudal end of the spinal cord was found at the L2-3 intervertebral space or above in 37 patients (35.6%) and below L2-3 level in 67 patients (64.4%). The diameter of the filum was <2 mm in 60 patients (57.7%) and > or =2 mm in 44 patients (42.3%). These data clearly indicate that the pre-operative diagnosis of adult TCS must rely primarily on the neurological symptomatology and the specific imaging feature, posterior displacement of the conus and filum that attach the posterior arachnid membrane.

Symptomatic protocols for adult tethered cord syndrome.

Diagnosis of tethered cord syndrome (TCS) is complicated because anatomical information is not adequate for this task. For example, recent studies have shown that the combination of an elongated cord and a thick filum terminale, demonstrated by MRI or at operation, is no longer an essential feature for the diagnosis of TCS. For TCS diagnosis, emphasis should rather be on its characteristic symptomatology and accentuated by postural changes, since TCS is a functional disorder of the lumbosacral spinal cord. In this report, the authors present the list of signs and symptoms pertinent to TCS in adult and late teenage patients to serve as a diagnostic means.

Concept of arteriovenous malformation compartments and surgical management.

Cerebral AVMs are known to be a source of intracranial hemorrhages and epileptic seizures. Their natural history indicates approximately 15% mortality and 35% morbidity over a 15-year period. This significant mortality and morbidity mandates a need for satisfactory treatment of this entity, ideally by elimination of AVMs. Microsurgical resection, endovascular embolization and radiosurgery (irradiation) are the three effective modes of treatment currently available. However, no objective criteria have been established for which mode(s) of treatment should be selected for individual patients with AVMs. Considering the complexity of AVMs and variable conditions of individual patients, neurosurgeons, intravascular interventionalists and radiosurgeons must make their own decisions on how to treat each patient based on their experience. In practice, treatment of small AVMs in non-functional areas is favored equally by each of these specialists, while they tend to avoid treatment of large AVMs, particularly those in functional areas of the brain. The authors report the surgical intervention of large AVMs, including those located in functional areas of the hemisphere by special techniques. One can demonstrate AVM compartments by using angiography and with the aid of color Doppler ultrasonography, each compartment can be outlined and dissected individually until all the compartments are isolated without causing any damage to the surrounding brain and the entire AVM is rendered shrunken and then removed. The concept of compartmental treatment of AVMs may be applied in the future to radiosurgery and intravascular embolization of large AVMs.

Pathophysiology of tethered cord syndrome: correlation with symptomatology.

Tethered cord syndrome (TCS) is a stretch-induced functional disorder of the spinal cord. The mechanical cause of TCS is an inelastic structure anchoring the caudal end of the spinal cord that prevents cephalad movement of the lumbosacral cord. Stretching of the spinal cord occurs in patients either when the spinal column grows faster than the spinal cord or when the spinal cord undergoes forcible flexion and extension. Research in patients and experimental animals suggests that there is a link between the clinical dysfunctions that characterize TCS and putative pathophysiological changes that accompany this syndrome. Among these changes are depression of electrophysiological activity and shifts in the reduction/oxidation ratio of cytochrome oxidase. The latter suggests that there is impairment of oxidative metabolism. These putative pathophysiological changes in TCS occur mainly within the lumbosacral cord under excessive tension. The authors discuss the pathophysiology of TCS and examine related symptoms.

Intrathecal endoscopy to enhance the diagnosis of tethered cord syndrome.

OBJECT: Tethered cord syndrome (TCS) is being diagnosed in an increasing number of adults and late teens. Before referral to neurosurgeons, however, the majority of patients in this group suffers back and leg pain for a long period without a definitive diagnosis. The diagnostic difficulty derives from 2 factors: the signs and symptoms are subtle and easily overlooked, and the combination of an elongated cord and a thickened filum is lacking in 65% of patients. When a patient presents with signs and symptoms typical for TCS but demonstrates no elongated cord or thickened filum on MR imaging, one must search for a more reliable finding to establish a diagnosis of TCS. Based on the authors' earlier surgical experiences, posterior displacement of the terminal filum is consistently found at surgery in all patients with TCS. In previous publications they interpreted this finding as the lower cord and filum traveling along the concave side of the lumbosacral spinal canal to minimize cord tension. In the present prospective study, the authors attempt to confirm posterior displacement of the filum terminale by using intrathecal endoscopy prior to wide exposure of the spinal cord and filum. Further, the stretch test was applied to the terminal filum to evaluate its elasticity. METHODS: Sixty-eight patients with signs and symptoms as well as MR imaging studies indicative of TCS underwent endoscopic examination of the filum and cauda equina. After lumbar or sacral laminectomy, a flexible endoscope was inserted through a small dural and arachnoid incision into the subarachnoid space. The filum and cauda equina fibers were identified. Once the dura mater and arachnoid were opened widely, a stretch test was done to confirm filum inelasticity. In 3 patients, percutaneous endoscopy was also performed before open surgery to determine its applicability as compared with the open method. RESULTS: On inserting the endoscope into the intrathecal space, the filum was immediately identified medioposterior to the cauda equina fibers in all 68 patients. The stretch test revealed a lack of filum elasticity in all patients. Preoperative percutaneous endoscopy was equally effective in identifying the position of the filum. CONCLUSIONS: Currently, endoscopic identification of the posteriorly displaced filum, which was confirmed at open surgery, is the essential diagnostic study for TCS or the tethered spinal cord. Furthermore, the stretch test of the filum proves its inelasticity, and filum sectioning leads to ascension and relaxation of the caudal spinal cord. These results can be linked to the impaired oxidative metabolism of the lumbosacral cord under excessive tension and to the metabolic and neurological improvements seen after filum sectioning.

Bypass coaptation for cervical root avulsion: indications for optimal outcome.

OBJECTIVE: Previously, we reported bypass coaptation of the C3 and C4 anterior rami to the upper trunk of the brachial plexus for restoration of the muscles denervated as a result of C5 and C6 nerve root avulsion. This procedure is thought to be superior to the transfer of individual peripheral nerve fibers to the brachial plexus branches. Therefore, the benefits of the bypass coaptation procedures in the treatment of various root avulsions are presented. METHODS: Twenty-six patients were selected as suitable candidates for bypass coaptation procedures. They were divided into 3 groups: 1) Erb-Duchenne palsy due to C5 and C6 root avulsion, 2) Klumpke palsy due to C8 and T1 root avulsion, and 3) the flail arm (or flail upper limb) due to C5 through T1 root avulsion. The surgical techniques are described in detail. RESULTS: The coaptation procedures for the first group resulted in excellent recovery of all the denervated muscles. The patients in the second group showed reinnervation of the finger muscles and finger sensory distributions in infants within the first year after surgery. The flail arm group regained satisfactory proximal muscle function but only mild distal muscle function. One exception was a child who showed significant recovery in proximal and distal motor and sensory function. CONCLUSION: We recommend the bypass coaptation as a useful procedure for the following categories: Erb-Duchenne palsy due to C5 and C6 root avulsion in all ages, Klumpke palsy due to the C8 and T1 avulsion, and the flail arm due to C5 through T1 avulsion in young children. However, bypass procedures for the flail limb in adults require additional innovative methods to facilitate the growth rate of regenerating nerves.

What is the true tethered cord syndrome?

INTRODUCTION: The tethered cord syndrome (TCS) is a stretch-induced functional disorder of the spinal cord with its caudal part anchored by an inelastic structure. DISCUSSION: This article clarifies the reversible lesions that occur in the cord segments above any of the inelastic abnormalities. These lesions are found mostly in the lumbosacral cord, occasionally in the cervical cord and closely correlate with clinical findings. Imaging studies alone do not allow accurate diagnosis of the TCS. The authors emphasize the importance of adhering to the physiological terms "tethered cord syndrome" and "tethered spinal cord" to avoid controversies derived from terms that are not based on the pathophysiology of TCS.