Safety and effectiveness of the assessment and treatment of idiopathic normal pressure hydrocephalus in the Adult Hydrocephalus Clinical Research Network

OBJECTIVE

The aim of this study was to describe the processes and outcomes associated with patients at five sites in the Adult Hydrocephalus Clinical Research Network (AHCRN) who had undergone evaluation and treatment for suspected idiopathic normal pressure hydrocephalus (iNPH) and had 1-year postoperative follow-up.

METHODS

Subjects with possible iNPH who had been prospectively enrolled in the AHCRN registry between November 19, 2014, and December 31, 2018, were evaluated by CSF drainage via either lumbar puncture or external lumbar drainage, consistent with recommendations of the international iNPH guidelines. Standardized clinical evaluations of gait, cognition, urinary symptoms, depression, and functional outcomes were conducted at baseline, before and after CSF drainage, and at 4-month intervals after shunt surgery. Complications of CSF drainage and shunt surgery were recorded.

RESULTS

Seventy-four percent (424/570) of patients with possible iNPH had CSF drainage, and 46% of them (193/424) underwent shunt surgery. The mean change in gait velocity with CSF drainage was 0.18 m/sec in patients who underwent shunt surgery versus 0.08 m/sec in patients who did not. For shunt surgery patients, gait velocity increased by 54% from 0.67 m/sec before CSF drainage to 0.96 m/sec 8-12 months after surgery, and 80% of patients had an increase of at least 0.1 m/sec by the first postoperative visit. Evaluation of cognition, urinary symptoms, depression, and functional outcomes also revealed improvement after shunt surgery. Of 193 patients who had undergone shunt surgery, 176 (91%) had no complications and 17 (9%) had 28 complications. Eleven patients (6%) had 14 serious complications that resulted in the need for surgery or an extended hospital stay. The 30-day reoperation rate was 3%.

CONCLUSIONS

Using criteria recommended by the international iNPH guidelines, the authors found that evaluation and treatment of iNPH are safe and effective. Testing with CSF drainage and treatment with shunt surgery are associated with a high rate of sustained improvement and a low rate of complications for iNPH in the 1st year after shunt surgery. Patients who had undergone shunt surgery for iNPH experienced improvement in gait, cognitive function, bladder symptoms, depression, and functional outcome measures. Gait velocity, which is an easily measured, objective, continuous variable, should be used as a standard outcome measure to test a patient's response to CSF drainage and shunt surgery in iNPH.

Cognitive and gait outcomes after primary endoscopic third ventriculostomy in adults with chronic obstructive hydrocephalus

OBJECTIVE

The object of this study was to determine the short- and long-term efficacy of primary endoscopic third ventriculostomy (ETV) on cognition and gait in adults with chronic obstructive hydrocephalus.

METHODS

Patients were prospectively accrued through the Adult Hydrocephalus Clinical Research Network patient registry. Patients with previously untreated congenital or acquired obstructive hydrocephalus were included in this study. Gait velocity was assessed using a 10-m walk test. Global cognition was assessed with the Montreal Cognitive Assessment (MoCA). Only patients with documented pre- and post-ETV gait analysis and/or pre- and post-ETV MoCA were included.

RESULTS

A total of 74 patients had undergone primary ETV, 42 of whom were analyzed. The remaining 32 patients were excluded, as they could not complete both pre- and post-ETV assessments. The mean age of the 42 patients, 19 (45.2%) of whom were female, was 51.9 ± 17.1 years (range 19-79 years). Most patients were White (37 [88.1%]), and the remainder were Asian. Surgical complications were minor. Congenital etiologies occurred in 31 patients (73.8%), with aqueductal stenosis in 23 of those patients (54.8%). The remaining 11 patients (26.2%) had acquired cases. The gait short-term follow-up cohort (mean 4.7 ± 4.1 months, 35 patients) had a baseline median gait velocity of 0.9 m/sec (IQR 0.7-1.3 m/sec) and a post-ETV median velocity of 1.3 m/sec (IQR 1.1-1.4 m/sec). Gait velocity significantly improved post-ETV with a median within-patient change of 0.3 m/sec (IQR 0.0-0.6 m/sec, p < 0.001). Gait velocity improvements were sustained in the long term (mean 14 ± 2.8 months, 12 patients) with a baseline median velocity of 0.7 m/sec (IQR 0.6-1.3 m/sec), post-ETV median of 1.3 m/sec (IQR 1.1-1.7 m/sec), and median within-patient change of 0.4 m/sec (IQR 0.2-0.6 m/sec, p < 0.001). The cognitive short-term follow-up cohort (mean 4.6 ± 4.0 months, 38 patients) had a baseline median MoCA total score (MoCA TS) of 24/30 (IQR 23-27) that improved to 26/30 (IQR 24-28) post-ETV. The median within-patient change was +1 point (IQR 0-2 points, p < 0.001). However, this change is not clinically significant. The cognitive long-term follow-up cohort (mean 14 ± 3.1 months, 15 patients) had a baseline median MoCA TS of 23/30 (IQR 22-27), which improved to 26/30 (IQR 25-28) post-ETV. The median within-patient change was +2 points (IQR 1-3 points, p = 0.007), which is both statistically and clinically significant.

CONCLUSIONS

Primary ETV can safely improve symptoms of gait and cognitive dysfunction in adults with chronic obstructive hydrocephalus. Gait velocity and global cognition were significantly improved, and the worsening of either was rare following ETV.

Extended lumbar drainage in idiopathic normal pressure hydrocephalus: a systematic review and meta-analysis of diagnostic test accuracy

BACKGROUND

When appropriately selected, a high proportion of patients with suspected idiopathic normal pressure hydrocephalus (iNPH) will respond to cerebrospinal fluid diversion with a shunt. Extended lumbar drainage (ELD) is regarded as the most accurate test for this condition, however, varying estimates of its accuracy are found in the current literature. Here, we review the literature in order to provide summary estimates of sensitivity, specificity, positive- and negative predictive value for this test through meta-analysis of suitably rigorous studies.

METHODS

Studies involving a population of NPH patients with predominantly idiopathic aetiology (>80%) in which the intention of the study was to shunt patients regardless of the outcome of ELD were included in the review. Various literature databases were searched to identify diagnostic test accuracy studies addressing ELD in the diagnosis of iNPH. Those studies passing screening and eligibility were assessed using the QUADAS-2 tool and data extracted for bivariate random effects meta-analysis.

RESULTS

Four small studies were identified. They showed disparate results concerning diagnostic test accuracy. The summary estimates for sensitivity and specificity were 94% (CI 41-100%) and 85% (CI 33-100%), respectively. The summary estimates of positive and negative predictive value were both 90% (CIs 65-100% and 48-100%, respectively).

CONCLUSION

Large, rigorous studies addressing the diagnostic accuracy of ELD are lacking, and little robust evidence exists to support the use of ELD in diagnostic algorithms for iNPH. Therefore, a large cohort study, or ideally an RCT, is needed to determine best practice in selecting patients for shunt surgery.

The clinical spectrum of hydrocephalus in adults: report of the first 517 patients of the Adult Hydrocephalus Clinical Research Network registry

OBJECTIVE

The authors describe the demographics and clinical characteristics of the first 517 patients enrolled in the Adult Hydrocephalus Clinical Research Network (AHCRN) during its first 2 years.

METHODS

Adults ≥ 18 years were nonconsecutively enrolled in a registry at 6 centers. Four categories of adult hydrocephalus were defined: transition (treated before age 18 years), unrecognized congenital (congenital pattern, not treated before age 18 years), acquired (secondary to known risk factors, treated or untreated), and suspected idiopathic normal pressure hydrocephalus (iNPH) (≥ age 65 years, not previously treated). Data include etiology, symptoms, examination findings, neuropsychology screening, comorbidities, treatment, complications, and outcomes. Standard evaluations were administered to all patients by trained examiners, including the Montreal Cognitive Assessment, the Symbol Digit Modalities Test, the Beck Depression Inventory–II, the Overactive Bladder Questionnaire Short Form symptom bother, the 10-Meter Walk Test, the Boon iNPH gait scale, the Lawton Activities of Daily Living/Instrumental Activities of Daily Living (ADL/IADL) questionnaire, the iNPH grading scale, and the modified Rankin Scale.

RESULTS

Overall, 517 individuals were enrolled. Age ranged from 18.1 to 90.7 years, with patients in the transition group (32.7 ± 10.0 years) being the youngest and those in the suspected iNPH group (76.5 ± 5.2 years) being the oldest. The proportion of patients in each group was as follows: 16.6% transition, 26.5% unrecognized congenital, 18.2% acquired, and 38.7% suspected iNPH. Excluding the 86 patients in the transition group, who all had received treatment, 79.4% of adults in the remaining 3 groups had not been treated at the time of enrollment. Patients in the suspected iNPH group had the poorest performance in cognitive evaluations, and those in the unrecognized congenital group had the best performance. The same pattern was seen in the Lawton ADL/IADL scores. Gait velocity was lowest in patients in the suspected iNPH group. Categories that had the most comorbidities (suspected iNPH) or etiologies of hydrocephalus that directly cause neurological injury (transition, acquired) had greater degrees of impairment compared to unrecognized congenital, which had the fewest comorbidities or etiologies associated with neurological injury.

CONCLUSIONS

The clinical spectrum of hydrocephalus in adults comprises more than iNPH or acquired hydrocephalus. Only 39% of patients had suspected iNPH, whereas 43% had childhood onset (i.e., those in the transition and unrecognized congenital groups). The severity of symptoms and impairment was worsened when the etiology of the hydrocephalus or complications of treatment caused additional neurological injury or when multiple comorbidities were present. However, more than half of patients in the transition, unrecognized congenital, and acquired hydrocephalus groups had minimal or no impairment. Excluding the transition group, nearly 80% of patients in the AHCRN registry were untreated at the time of enrollment. A future goal for the AHCRN is to determine whether patients with unrecognized congenital and acquired hydrocephalus need treatment and which patients in the suspected iNPH cohort actually have possible hydrocephalus and should undergo further diagnostic testing. Future prospective research is needed in the diagnosis, treatment, outcomes, quality of life, and macroeconomics of all categories of adult hydrocephalus.

Traumatically induced lymphangioma of the ulnar nerve. Case report

Lymphangiomas, benign hamartomatous lesions involving lymphatic tissue, result from a failure of lymphatic channels to communicate with the venous system or normal lymphatic channels. The authors describe a case in which a lymphangioma arising within the ulnar nerve developed after trauma to the same area. This is the second reported case of a lymphangioma that originated from a peripheral nerve and the first case in which the lesion was associated with trauma. The authors propose that a lymphangioma involving the peripheral nerve may be the result of trauma.

Axonal cytoskeleton changes in experimental optic neuritis

Axonal loss and degeneration in multiple sclerosis (MS) and experimental allergic encephalomyelitis (EAE) have been suggested by brain imaging, pathological and axonal transport studies. Further elucidation of the processes and mechanisms of axonal degeneration in demyelinating diseases is therefore of potential importance in order to alleviate the permanent disabilities of MS patients. However, detailed studies in this area are impeded by the small number of reliable models in which the onset and location of demyelination can be well-controlled. In this study, microinjection of polyclonal rabbit anti-galactocerebroside (anti-Gal C) antibody and guinea pig complement was used to induce local demyelination in the rat optic nerve. We found that treatment with appropriate volumes of the antibody and complement could induce local demyelination with minimal pressure- or trauma-induced damage. Local changes in neurofilaments (NFs) and microtubules (MTs) were examined with both immunohistochemistry (IHC) and electron microscopy (EM). On day 1 after microinjection, we observed moderate NF and MT disassembly in the local demyelinated area, although in most cases, no apparent inflammatory cell infiltration was seen. The NF and MT changes became more apparent on days 3, 5, 7 after microinjection, along with gradually increased inflammatory cell infiltration. These results suggested that acute demyelination itself may induce local cytoskeleton changes in the demyelinated axons, and that the ensuing local inflammation may further enhance the axonal damage. When the lesions were stained with specific antibodies for T lymphocytes, macrophages, and astrocytes, we found that most of the cells were macrophages, suggesting that macrophages may play a greater role in inflammation-related axonal degeneration and axonal loss. These results were confirmed and further characterized on the ultrastructural level.

Congenital entrapment of the lateral cutaneous nerve of the calf presenting as a personal sensory neuropathy

OBJECTIVE

Presentation of an unusual case of congenital entrapment of the lateral cutaneous nerve of the calf (LCNC) mimicking a peroneal sensory neuropathy.

METHODS

We report the case of as 16-year-old girl with a 3 year history of progressive tingling, numbness and pain in her right calf precipitated by athletic activities involving repeated flexion and extension of the knee. A Tinel's sign was present over the common peroneal nerve in the distal popliteal fossa but absent at the fibular neck. Motor and sensory examination of the common peroneal nerve was normal as were electrophysiological studies and MRI.

RESULTS

At surgery, the LCNC, a sensory branch of the common peroneal nerve, was entrapped at a point where it pierced the tendon of the biceps femoris muscle. Transection of the part of the tendon overlying the LCNC resulted in complete and permanent relief of symptoms.

SIGNIFICANCE AND CONCLUSION

The proximal location of the Tinel's sign, absence of motor or sensory deficits and normal electrophysiology suggested, preoperatively, that this was not an entrapment of the common peroneal nerve at the fibular neck but rather a more proximal abnormality likely involving only a part of the peroneal nerve or one of its sensory branches. As a result, the more proximal exposure of the peroneal nerve within the popliteal fossa revealed entrapment of the neuropathy of the common peroneal nerve or one of its branches, due to a normal nerve piercing an otherwise normal tendon. Secondly, there are no previously reported cases of surgically documented compression of the LCNC in an otherwise normal patient (i.e. non-diabetic).

Head injuries due to falls caused by seizures: a group at high risk for traumatic intracranial hematomas

This prospective review of adult patients with head injuries examines the incidence of head injuries due to falls caused by seizures, the incidence and severity of intracranial hematomas, and the morbidity and mortality rates in this patient population. A head injury was attributed to a fall caused by a seizure if the seizure was witnessed to have caused the fall, or the patient had a known seizure history, appeared postictal or was found convulsing after the fall, and no other cause for the fall was evident. A total of 1760 adult head-injured patients were consecutively admitted to the authors' service between 1986 and 1993. Five hundred eighty-two head injuries (33.1%) were due to falls and 22 (3.8%) of these were caused by seizures. Based on the prevalence rates for epilepsy in the general population of 0.5 to 2%, these results indicate that epileptics are several times more likely to suffer a head injury due to a fall. Mass lesions were found in 20 (90.9%) of these 22 patients and the remaining two patients suffered mild diffuse head injuries. There was a high incidence of extraaxial mass lesions: 17 (85%) of the 20 intracranial hematomas were either epidural (five cases) or acute subdural (12 cases) hematomas. Eighteen (81.8%) of the 22 patients required evacuation of a hematoma. Both the incidence of intracranial hematomas (90.9% vs. 39.8%, p < 0.001, chi-square analysis) and the rate of hematoma evacuation (81.8% vs. 32.3%; p < 0.001) was significantly greater in patients injured in falls due to seizures (22 cases) than in the group injured in falls from all other causes (560 cases). The higher incidence of hematomas and the need for evacuation were not explained by differences in age, seventy of head injury, or incidence of alcohol intoxication. Despite the greater incidence of mass lesions and the need for operative treatment in patients injured because of seizures, their mortality rate was similar to that of patients injured in falls from other causes. On the basis of their review of patients admitted to a neurosurgical center with complaints of head injury, the authors conclude that patients with head injuries due to a fall caused by a seizure should undergo computerized tomography scanning early in their management. Until a mass lesion has been excluded, any decrease in level of consciousness or focal neurological deficit should not be attributed to the seizure itself.

Neurologic trauma concerns

Patients with underlying medical illnesses or conditions will comprise a progressively larger proportion of head-injury patients given the aging of the general population and improved survival in serious illnesses. Age and underlying illness can influence the presentation, management, and outcome of head injuries by increasing the frequency, severity, and complications from head injury. This article examines the conditions that are most often associated with head injury.

Synapse formation and preferential distribution in the granule cell layer by regenerating retinal ganglion cell axons guided to the cerebellum of adult hamsters

To investigate constraints and preferences for synaptogenesis in the injured mammalian CNS, regenerating retinal ganglion cell (RGC) axons of adult hamsters were guided through a peripheral nerve (PN) graft to a target they do not usually innervate: the cerebellum (Cb). When identified by the presence of HRP anterogradely transported from the retina 2-9 months later, such RGC axons were found to have extended into the cerebellar cortex for up to 650 microns. Most of this growth was in the granule cell layer (GCL) and only a few axons entered the molecular layer. The preference for the GCL could not be explained by the position of the PN graft in the Cb, a selective denervation of the GCL, local damage to other neurons, or the distribution of reactive gliosis in the vicinity of the graft. Furthermore, by EM, more than 95% of the labeled retinocerebellar terminals and synapses were in the GCL. Retinocerebellar terminals were larger and contained more synapses than the regenerated RGC terminals previously studied in the superior colliculus. These results indicate that regenerating axons of CNS neurons can form persistent synapses with novel targets. The preferential synaptogenesis in the GCL suggests that such unusual connections are not formed randomly in the CNS of these adult mammals.

Spinal cord concussion

The hallmark of concussion injuries of the nervous system is the rapid and complete resolution of neurological deficits. Cerebral concussion has been well studied, both clinically and experimentally. In comparison, spinal cord concussion (SCC) is poorly understood. The clinical and radiological features of 19 SCC injuries in the general population are presented. Spinal cord injuries were classified as concussions if they met three criteria: 1) spinal trauma immediately preceded the onset of neurological deficits; 2) neurological deficits were consistent with spinal cord involvement at the level of injury; and 3) complete neurological recovery occurred within 72 hours after injury. Most cases involved young males, injured during athletics or due to falls. Concussion occurred at the two most unstable spinal regions, 16 involving the cervical spinal and three the thoracolumbar junction. Fifteen cases presented with combined sensorimotor deficits, while four exhibited only sensory disturbances. Many patients showed signs of recovery with the first few hours after injury and most had completely recovered within 24 hours. Only one case involved an unstable spinal injury. There was no evidence of ligamentous instability, spinal stenosis, or canal encroachment in the remaining 18 cases. Two patients, both children, suffered recurrent SCC injuries. No delayed deterioration or permanent cord injuries occurred. Spinal abnormalities that would predispose the spinal cord to a compressive injury were present in only one of the 19 cases. This suggests that, as opposed to direct cord compression, SCC may be the result of an indirect cord injury. Possible mechanisms are discussed.

Ultralight aircraft crashes: their increasing incidence and associated fractures of the thoracolumbar spine

Ultralight aircraft, which originated in 1975 in the U.S. and have been available in Canada since 1980, have enjoyed a tremendous increase in popularity to the point where it is estimated that there are close to 20,000 ultralights in North America today. Two reasons account for their growing popularity: relatively low cost and simplicity, allowing almost any person to enjoy the sport of flying, which was unattainable for most just a few years ago. Unfortunately, inexperienced pilots and relatively new and unproven aircraft have been brought together to create a potentially lethal combination. On average, 60 deaths per year occur in the U.S. due to ultralight crashes, a number that will undoubtedly rise in the future. The U.S. and Canada have very few regulations covering the licensing of pilots or the design and construction of ultralight aircraft. The North American safety record is inferior to that of countries that have implemented stricter, more far-reaching regulations. Stricter pilot certification and enforced regulations governing design and construction of ultralight aircraft would improve the safety record of this sport. Ultralight aircraft crashes and their associated injuries came to our attention recently through the presentation of three cases of isolated fractures of the thoracolumbar spine in such crashes. Spinal fractures due to ultralight crashes have no unique features that separate them from those of other trauma victims. Physicians must, however, have a high index of suspicion for spinal injuries in these victims.

Osteoid osteoma of the cervical spine: case reports and literature review

Osteoid osteoma, a benign osteoid-forming tumour, may be found in any bone in the body. Approximately 10% of cases involve the most common site and the cervical region the second commonest site for spinal osteoid osteomas. Two new cases of cervical spine osteoid osteoma are presented and the 21 previously reported cases are reviewed. This cervical spine tumour should be considered as a possible diagnosis in any young person complaining of neck or upper back pain, especially if the pain is worse at night, is relieved by salicylates and is accompanied by tenderness, neck stiffness and scoliosis of rapid onset. Detailed radiologic investigation aids in the diagnosis and accurately locates the lesion. Surgery is the definitive treatment and complete resection of the tumour results in rapid and permanent relief of pain.