2012 Olympics: who will survive?
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Exercise↗
Biomedical subjects
P J Hamlyn
Publications and source records attributed to P J Hamlyn.
NG2 proteoglycan expression in the peripheral nervous system: upregulation following injury and comparison with CNS lesions.
The chondroitin sulphate proteoglycan NG2 blocks neurite outgrowth in vitro and thus may be able to inhibit axonal regeneration in the CNS. We have used immunohistochemistry to compare the expression of NG2 in the PNS, where axons regenerate, and the spinal cord, where regeneration fails. NG2 is expressed by satellite cells in dorsal root ganglia (DRG) and in the perineurium and endoneurium of intact sciatic nerves of adult rats. Endoneurial NG2-positive cells were S100-negative. Injury to dorsal roots, ventral rami or sciatic nerves had no effect on NG2 expression in DRG but sciatic nerve section or crush caused an upregulation of NG2 in the damaged nerve. Strongly NG2-positive cells in damaged nerves were S100-negative. The proximal stump of severed nerves was capped by dense NG2, which surrounded bundles of regenerating axons. The distal stump, into which axons regenerated, also contained many NG2-positive/S100-negative cells. Immunoelectron microscopy revealed that most NG2-positive cells in distal stumps had perineurial or fibroblast-like morphologies, with NG2 being concentrated at the poles of the cells in regions exhibiting microvillus-like protrusions or caveolae. Compression and partial transection injuries to the spinal cord also caused an upregulation of NG2, and NG2-positive cells and processes invaded the lesion sites. Transganglionically labelled ascending dorsal column fibres, stimulated to sprout by a conditioning sciatic nerve injury, ended in the borders of lesions among many NG2-positive processes. Thus, NG2 upregulation is a feature of the response to injury in peripheral nerves and in the spinal cord, but it does not appear to limit regeneration in the sciatic nerve.
Animals↗
Stereotactic radiosurgery for primary trigeminal neuralgia: state of the evidence and recommendations for future reports.
OBJECTIVE: To identify systematically all the studies reporting outcomes and complications of stereotactic radiosurgery for trigeminal neuralgia and to evaluate them against predefined quality criteria. METHODS: Inclusion criteria for outcome analysis included thorough demographic documentation, defined diagnostic and outcome criteria, a minimum of 30 patients treated with 12 months median/mean follow up, not more than 20% lost to follow up, Kaplan-Meier actuarial analysis, primary trigeminal neuralgia, not more than 10% of patients retreated for failure or early recurrence, and minimum dose of 70 Gy. RESULTS: Of 38 studies identified, four could be used to evaluate rates of pain relief on a yearly basis, and two for actuarial rates of complete pain relief; seven provided data on latencies and 18 were used to evaluate complications. Pain relief typically occurs within three months. Complete relief is initially achieved by three quarters of the patients, but half maintain this outcome at three years. One half or less can permanently stop drug treatments. Sensory disturbance, including anaesthesia dolorosa, is the most frequent complication of stereotactic radiosurgery. CONCLUSIONS: Outcomes after stereotactic radiosurgery appear in line with other ablative techniques. Results are better when it is used as primary treatment in patients with typical symptoms. Current data are largely observational and the quality is generally poor. This technique should be evaluated in a randomised, controlled trial with universal outcome measures, actuarial methodology, and validated measures of patient satisfaction and quality of life.
Follow-Up Studies↗
A new anterior cervical instrumentation system combining an intradiscal cage with an integrated plate: an early technical report.
STUDY DESIGN: To provide a technical report on a new device. Early outcome assessment of patients undergoing anterior cervical decompression and stabilization with the described technique. OBJECTIVES: To detail the operative and technical aspects of the new anterior cervical instrumentation and to identify its suitability for an extensive clinical study. SUMMARY OF BACKGROUND DATA: The controversy over the need for fusion in the surgery of cervical disc disease is in part fueled by the absence of an ideal technique. However, the design of the integrated anterior cervical plate and cage device (PCB) appears to provide immediate stability and to restore disc height and cervical lordosis in addition to reducing graft recipient and donor site-related complications. METHODS: After a standard anterior cervical discectomy and preparation of the disc space, the correct size of the cage with integrated plate is inserted. Self-tapping screws are inserted without image intensifier. Cancellous bone chips are used. The technique was used in 29 patients that were followed prospectively from 5 to 24 months (median 8 months, interquartile range 6-15 months). RESULTS: The technique was easy to learn and implement. The authors' experience has been free of intraoperative complications. After surgery no screw backout or device failure was identified. Twenty-seven patients improved clinically. Donor site morbidity was trivial. No collars were applied after surgery. CONCLUSIONS: The design of the system appears to prevent bone-graft recipient site and donor site complications, provides immediate biomechanical stability, prevents screw backout or breakage, and restores posterior interbody height and lordosis. The device is of sufficient promise to warrant further close evaluation focusing on long-term outcome. The new radiolucent version has potential advantages for the assessment of fusion.
Bone Plates↗
Familial colloid cysts of the third ventricle: case report.
OBJECTIVE AND IMPORTANCE: Familial colloid cysts of the third ventricle are very rare. This is the largest family reported and the first in which all affected members are female and all members have been screened. Screening led to the diagnosis of an asymptomatic case of a colloid cyst of the third ventricle, and the management of that lesion is discussed. CLINICAL PRESENTATION: A mother and two daughters who were diagnosed with colloid cysts of the third ventricle, from a family containing four sisters, three brothers, and the father, are presented. INTERVENTION: The index patient (Patient 2) underwent computed tomographic scanning-guided stereotactic transcallosal excision of her colloid cyst. Her siblings and her father were screened using magnetic resonance imaging as well as computed tomographic scanning. Cytogenetic analysis of blood samples obtained from the patient and her family revealed no chromosomal abnormalities. CONCLUSION: Screening is of value for families in which two or more members are affected. The management of asymptomatic cases is influenced by the lesion size and the age and fitness of the patient.
Adult↗
The effects of FK506 on dorsal column axons following spinal cord injury in adult rats: neuroprotection and local regeneration.
There is considerable evidence that immunophilin ligands can promote the regeneration of axons in peripheral nerves and act as neuroprotective agents in the CNS. We have examined the effects of FK506 and GPI 1046 on the responses to partial transection of ascending spinal dorsal column axons at T9, in some cases combined with crush of one sciatic nerve. FK506 (0.5 or 2.0 mg/kg) and GPI 1046 (10 or 40 mg/kg) was administered subcutaneously immediately after surgery and five times a week thereafter. Some animals received methylprednisolone (MP) (two subcutaneous doses of 30 mg/kg) in addition to, or instead of, FK506. After survival times of 1-12 weeks, dorsal column axons were labeled transganglionically with cholera toxin B-HRP. There was massive axonal sprouting at the lesion sites in animals with sciatic nerve injury and immunophilin ligand treatment. In FK506-treated animals a few severed sensory axons regenerated for up to 10 mm rostral to the lesion. Of greater significance, 30% of 71 FK506-treated animals had spared axons in the dorsal column, extending to the nucleus gracilis, versus 8% of 50 control animals (P < 0.05), showing that FK506 reduces the likelihood of axonal destruction due to secondary injury. A combination of FK506 and MP afforded greater protection than MP alone (P < 0.05), but axonal survival was not affected by sciatic nerve crush, dose of FK506, or survival time after injury. GPI 1046 (n = 11) did not promote axonal survival. Thus FK506 protects axons from secondary injury following spinal cord trauma, and in this experimental model, its neuroprotective effect is greater than that of MP.
Animals↗
Carotoid artery thrombosis following a penetrating oro-pharyngeal injury of unusual aetiology.
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Adult↗
Neurovascular relationships in the posterior cranial fossa, with special reference to trigeminal neuralgia. 1. Review of the literature and development of a new method of vascular injection-filling in cadaveric controls.
Vascular compression of cranial nerves adjacent to the brain stem has been implicated in a wide variety of disorders affecting their function. The considerable conflicts in published results relate primarily to flaws in study design. The design required of an adequate study is defined and a technique is presented, in 16 fresh human cadavers, of reliable and physiological injection-filling of both the cerebral arterial and venous systems. It allowed for the accurate observation of the normal neurovascular relationships in the posterior cranial fossa during operative simulation. Part 2 of this article concerns the use of this design in the study of trigeminal neuralgia, a disorder thought to relate to vascular compression of the fifth cranial nerve.
Adult↗
Neurovascular relationships in the posterior cranial fossa, with special reference to trigeminal neuralgia. 2. Neurovascular compression of the trigeminal nerve in cadaveric controls and patients with trigeminal neuralgia: quantification and influence of method.
The theory of neurovascular compression has been tested by comparing the neurovascular relationships of the trigeminal nerve in a series of operative observations in patients affected by trigeminal neuralgia with those of a control series of cadavers matched for age, sex and side, in which operative conditions were simulated during simultaneous arterial and venous injection--filling to physiological pressures, as described in Part 1 of this article. A rigorous system of classification of neurovascular relations is defined. In 46 patients with trigeminal neuralgia, 91% had a vessel in contact with the trigeminal nerve adjacent to the brain stem and in all but one a groove was created. Multiple vessels were found in 17% and in two both the root entry zone and lateral portions of the nerve were compressed. However, in 35 randomly selected fresh cadavers, not known to have suffered neurological disease, 14% had neurovascular contact and a further 26% had vessels "near" to the nerve. No vessel was associated with a groove and no multiple vessels, or sites of contact, were encountered. The difference between the control cadavers and the operative findings in patients related to an increase in the number of arteries. Injection-filling of the cadaveric vessels doubled the numbers of vessels in contact with, and near to the nerve. The technique used and system of classification applied showed an association between arterial contact and trigeminal neuralgia. The technique may provide a suitable method for the testing of the neurovascular compression theory in other conditions.
Adult↗
Prospective study of zero drift in fiberoptic pressure monitors used in clinical practice.
One hundred and one fiberoptic pressure transducers (59 subdural and 42 ventricular) were studied in 86 patients (some in whom more than one device had been inserted). Only four complications occurred: two transient cerebrospinal fluid leaks after removal and two clinically insignificant intracerebral hematomas. No intracranial infections could be attributed to the devices. Technical problems occurred 23 times, with 11 devices ceasing to function before removal, seven becoming displaced, and five microventricular catheters failing to enter the ventricles. Zero-drift readings were obtained for 83 devices at the time of removal (median 66 hours after insertion, range 2 hours-13 days). There was a clear negative bias in the readings (median -3), with a wide range of values (-12 to +14 mm Hg; interquartile range -6 to -1) that was apparent even in the first 3 days of use. There was no important relationship between zero drift and any recorded variable. It is concluded that zero drift of fiberoptic pressure transducers is a significant problem and that undue reliance should not be placed on intracranial pressure readings from these devices in isolation from other clinical and radiological information.
Equipment Failure↗
An anomaly in the nerve supply of the trapezius muscle.
Controversy surrounds the nerve supply to the trapezius muscle. We report a single specimen, from a series of dissections designed to study the intradural and peripheral course of the spinal part of the accessory nerve (sp.XI), in which the nerve failed to supply the trapezius muscle, whose supply came entirely from the cervical plexus. This provides anatomical support for the view that the supply from the cervical plexus may contain motor fibers and helps to explain why the sacrifice of the accessory nerve in radical neck dissection does not always produce complete paralysis of the trapezius muscle.
Cervical Plexus↗
A prospective comparison of fibre-optic and fluid-filled single lumen bolt subdural pressure transducers in ventilated neurosurgical patients.
A clinical comparison was made between fibre-optic and fluid-filled Bolt subdural pressure transducers in ventilated head injured patients. Twelve subjects had both devices inserted in neighbouring sites. In two patients there were obvious technical problems with the fibre-optic system and the results were therefore excluded from further analysis. In the remaining 10 patients, 2167 pairs of simultaneous recordings were made for up to 9 days and the degree of correspondence studied. A quarter of paired readings differed by more than 5 mmHg. There was no evidence of any overall bias, but in individual patients one device often read higher or lower than the other. The proportion of closely corresponding readings tended to diminish after 4 days. Therapeutically relevant episodes, where treatment might have been initiated on the basis of the readings from only one of the two systems, were equally likely with both devices and occurred on average approximately every 30 h. The relative accuracy of the two devices remains uncertain, but there is evidence suggesting that both were prone to errors.
Adolescent↗
Neurenteric cyst of the anterior cranial fossa.
Neurenteric cysts are uncommon developmental cysts of the central nervous system lined by epithelium of intestinal origin. We describe a cyst in the anterior cranial fossa, which has not been previously reported.
Adult↗
Localisation of immunoreactive factor VIII, nitric oxide synthase, substance P, endothelin-1 and 5-hydroxytryptamine in human postmortem middle cerebral artery.
This pre-embedding electron-immunocytochemical study investigated the localisation of endothelial (type III) and neuronal (type I) isoforms of nitric oxide synthase, substance P, endothelin-1 and 5-hydroxytryptamine in the human middle cerebral artery taken up to 40 h postmortem. To ¿recover' from the anoxic period some of the vessels were incubated in oxygenated Krebs solution prior to the immunoprocedure. At this long postmortem time, immunoreactivity to type III and type I nitric oxide synthase, substance P, endothelin-1 and 5-hydroxytryptamine was found in a subpopulation of intact cells present in the vessel intima; immunoreactivity to type I nitric oxide synthase was also observed in a subpopulation of adventitial perivascular nerve fibres. Cultures of the cells from the intima of the postmortem vessels showed that the cells were proliferating and positive immunoreactivity to factor VII identified them as endothelial cells. The results therefore indicate that even after up to 40 h postmortem, endothelium of human middle cerebral artery is immunoreactive for a number of vasoactive agents and perivascular nerve fibres show nitric oxide synthase immunoreactivity.
Aged↗
The innervation of the trapezius muscle: a cervical motor supply.
Controversy surrounds the nerve supply to the trapezius muscle. Anatomical studies have revealed independent connections from the C3 and C4 roots of the cervical plexus directly to the trapezius muscle. The objective of this study was to determine if these nerve bundles contain motor fibres and thus constitute an additional motor supply to trapezius. From a study of 32 cadavers, a representative example was chosen. Using a high powered operating microscope it was seen that such fibres were traceable to the ventral roots of the spinal cord. It is generally accepted that fibres in the ventral roots of the spinal cord are motor and thus, in this specimen, the trapezius muscle appeared to receive a direct motor supply from the cervical plexus independent of the accessory nerve.
Cervical Plexus↗
Neurovascular compression in trigeminal neuralgia: a clinical and anatomical study.
Neurovascular decompression is a widely practiced technique for the treatment of trigeminal neuralgia, and yet there is still debate as to whether the beneficial effect results from relieving the nerve of compression by an anatomically abnormal vessel or from the manipulation and trauma the nerve undergoes during the procedure. The development of this operation has been hampered by the lack of adequate anatomical studies in normal controls. The authors present a combined study of clinical and anatomical material employing standardized definitions of the neurovascular relationships in both groups. Detailed simulations of the operative procedure were carried out on fresh cadavers matched for age, sex, and side, and a technique of in situ blood vessel perfusion was developed that enabled the normal neurovascular arrangement to be observed post mortem at physiological pressures. Neurovascular compression, typified by a large vessel distorting and creating a groove in the fifth cranial nerve, was found in 37 of the 41 cases of trigeminal neuralgia; recurrence of pain did not relate to the site of compression. A follow-up study was carried out for a median of 53 months (range 12 to 103 months). No distortion was found in a total of 50 normal cadaveric dissections; however, on perfusion to physiological pressures, the percentage of nerves with vessels adjacent or in simple contact increased from 16% to 40%. This study using this new technique confirms that vascular compression of the fifth cranial nerve is an anatomical abnormality specific to trigeminal neuralgia.
Adult↗
Protrusion of the first thoracic disk.
A case of lateral prolapse of the T-1/T-2 intervertebral disk is presented. The patient complained of pain radiating down the medial aspect of the forearm into the little and ring fingers. This was associated with a subjective sensory loss in the same distribution, intact reflexes, and no long tract signs. Oculosympathetic paralysis was not present. Twelve cases have been mentioned in the literature, only eight of which contain details of the neurological findings. The varied findings in these cases are also reviewed, and it is noted that unless radiological examination includes the upper thoracic spine in cases of brachial neuralgia, these lesions will be missed.
Aged↗
Preliminary experience with the Berger neurobiopsy device for ultrasound guided aspiration and biopsy of intracranial lesions.
Our preliminary experience is presented in the use of the Berger neurobiopsy device for ultrasound localization and biopsy of intracranial lesions through a burr hole. The apparatus and technique are described, along with the results of its use in the first 49 patients. In these patients 43 tumours were biopsied, all except one successfully. Three abscesses were aspirated, two intraventricular shunt catheters were sited and in one patient the diagnosis of postradiation gliosis was confirmed and tumour excluded. The advantages and limitations of the technique are discussed. It is advocated as a simple and time-saving alternative to CT stereotactic biopsy in many cases.
Adolescent↗