To study the correlation of umbilical cord length with fetal parameters like Apgar score, sex, weight, and length, and its effect on labor outcome.
Prospective study of 1,000 cases.
Material and Method
Examination of umbilical cord was done for any loop around neck, trunk, etc; no. of loops of cord and positions; Knots of cord (True or false), any cord abnormalities. Fetal parameters recorded were sex, weight, and length of the newborn. Fetal outcome studied by Apgar score at 1 and 5 min.
In our study, the cord length varied from 24 to 124 cm. The mean cord length was 63.86 cm (±15.69 cm). Maximum cases seen were in the group of cord length between 51 and 60 cm. Lower 5th percentile was considered as short cord and upper 5th percentile was considered as long cord. Short-cord group was associated with significantly higher (p < 0.05) incidence of LSCS cases. Cord length did not vary according to the weight, length, and sex of the baby. The incidence of all types of cord complications increases as the cord length increases (p < 0.001*). Nuchal cords had higher mean cord length than in cases without nuchal cords (p < 0.001). As the number of loops in a nuchal cord increases to more than two loops, the operative interference increases. The significance was tested by using a Chi-square test, and it was found to be statistically significant (p < 0.05). Nuchal cords were seen to be associated with more cases of fetal heart abnormalities (p < 0.001). There is higher incidence of variability in fetal heart rate with extremes of cord length (p < 0.001). The incidence of birth asphyxia was significantly more in long and short cords as compared to cords with normal cord length (p < 0.001).
The present study showed that the length of umbilical cord is variable; however, maximum number of cases had normal cord length. Cases which had short and long cords constituted abnormal cord length. These cases had higher incidence of cord complications, increased incidence of operative interference, intrapartum complications, increased fetal heart rate abnormalities, and more chances of birth asphyxia. But cord length did not vary according to the weight, length, and sex of the baby.
Acute spinal cord ischemia syndrome is a rare condition comprising a small fraction of neurovascular accidents, the majority of which occur within the cerebral circulation. The circulation of the spinal cord has several unique features that determine the clinical presentation.
In this case of a 67-year-old Caucasian man who came to our emergency department with sudden-onset, severe right-sided pain and bilateral upper limb weakness, an atypical pattern of sensory deficit was observed. In this case report, we review acute spinal cord ischemia syndrome and consider the pathophysiology, diagnostic measures and prognostic factors associated with patient recovery.
Acute spinal cord ischemia syndrome with atypical patterns of sensory deficit is uncommon. Clinicians must consider acute spinal cord ischemia syndrome when assessing all patients with acute neck pain and focal neurological deficits; atypical presentations can present a diagnostic challenge. Current knowledge of the long-term outcome in patients with spinal cord ischemia is based on only a few small studies, some of which are discussed here.
In this report, we describe a rare cause of in utero fetal death, a complex entanglement of the umbilical cord around the fetal neck. At the 16th gestational week of pregnancy, routine fetal ultrasonography showed no fetal heartbeat. Thereafter, the fetus was delivered vaginally in the breech presentation. The neck was found to be encircled by multiple tight loops of the umbilical cord. Other than a thin and elongated neck, there were no dysmorphic features and no chromosomal abnormality on cytogenetic analysis.
Split cord malformations (SCMs) usually present in childhood, and are rarely reported in adults. And also, a cervicothoracic SCM associated with tethered cord syndrome has very rarely been reported in the literature. We report a case of SCM associated with tethered cord and spina bifida in an adult. This report describes the case of a 34-year-old woman who presented for evaluation of neck pain, back pain, and intermittent paraparesis of several months duration. The MRI and CT showed a SCM at the cervicothoracic level and a fibrous septum at the thoracic level. She underwent surgery for the SCM and tethered cord syndrome, and was followed for 7 years. Patient presented complete recovery in the follow-up. The authors discuss this unusual lesion and describe the anatomical relationship of the level of cord duplication and fibrous septum.
Split cord malformation; Adult; Tethered cord syndrome
A 21-year-old division I collegiate football player who had a history of several stingers presented with 5 days of persistent left neck and shoulder pain associated with paresthesias and upper extremity weakness. His symptoms began immediately during a game when he was struck on the right side of his helmet, which induced a compression-extension mechanism of injury to his neck. Clinical and electrodiagnostic evaluation was consistent with a left C5 radiculopathy, but magnetic resonance imaging of the cervical spine yielded normal results. The mean subaxial cervical space available for the cord (MSCSAC) index is a novel tool to predict chronic stinger syndrome. It is calculated by subtracting the sagittal diameter of the spinal cord from the disc-level sagittal diameter of the spinal canal at levels C3 through C6 and then averaging these values. A cutoff of < 4.3 mm has been shown to predict a greater-than-13-fold increase in risk of developing chronic stinger syndrome. This patient had a MSCSAC index of 3.2 mm, which correlated with his history of multiple stingers. The MSCSAC index may be a useful tool to help counsel athletes on the risk of developing future stingers, although more extensive research on this measurement tool is indicated.
stinger; burner; radiculopathy; cervical spondylosis
In reports from the UK and New Zealand, it is noted that the incidence of rugby injuries to the cervical spinal cord has dropped and that the percentage of players injured in the tackle has similarly decreased. In contrast, this does not appear to be the pattern in South Africa and an analysis has therefore been made of 40 rugby players sustaining injuries to the spinal cord during the period 1985 to 1989. The radiological appearances on admission have been correlated with the circumstances of injury, associated orthopaedic injuries and neurological deficits. The tackle was responsible for the majority of injuries, causing more than the scrum. Tackles were also responsible for more cases of complete, permanent quadriplegia than the scrum. The commonest cause of injury in players being tackled was the high tackle around the neck, while the commonest cause of injury in players making the tackle was the dive tackle. This survey has shown that the tackle is now the major cause of spinal cord injury in South African rugby, in contrast to earlier analyses in which the scrum was identified as the most common cause.
We have observed a higher rate of Lhermitte's syndrome (LS) after chemo-IMRT of head and neck cancer than the published rates after conventional radiotherapy. We hypothesized that the inhomogeneous spinal cord dose distributions produced by IMRT caused a “bath and shower” effect, characterized by low doses in the vicinity of high doses, reducing spinal cord tolerance.
Methods and Materials
73 patients with squamous cell carcinoma of the oropharynx participated in a prospective study of IMRT concurrent with weekly carboplatin and taxol. 15 (21%) reported LS in at least 2 consecutive follow-up visits. Mean dose, maximum dose, partial (Vd) as well as the absolute volume (cc) of spinal cord receiving specified doses (≥10 Gy, 20 Gy, 30 Gy, 40 Gy), and the pattern of dose distributions at the “anatomical” (from the base of the skull to the aortic arch) and “plan-related” (from the top through the bottom of the PTV's) spinal cords were compared between LS and 34 non-LS patients.
LS patients had significantly higher spinal cord mean doses, V30, V40, and volumes receiving ≥30 and ≥ 40 Gy compared to the non-LS patients (p < 0.05). Strongest predictors of LS were higher V40 and higher cord volumes receiving ≥40 Gy (p ≤ 0.007). There was no evidence of larger spinal cord volumes receiving low doses in the vicinity of higher doses (“bath and shower”) in LS compared to non-LS patients.
Greater mean dose, V30, V40, and cord volumes receiving ≥30 and ≥40 Gy characterized LS compared to non-LS patients. “Bath and shower” effects could not be validated in this study as a potential contributor to LS. The higher than expected rates of LS may be due to the specific concurrent chemotherapy agents, or to more accurate identification of LS in the setting of a prospective study.
Lhermitte's syndrome; Predictive factors; Head and neck cancer; Bath and shower effect; IMRT
Objective: To alert athletic trainers to the importance of recognizing the signs and symptoms of central cord syndrome.
Background: A 15-year-old high school wrestler was found lying supine on the mat after sustaining a hyperextension injury to his neck while drilling during practice, complaining of numbness, tingling, and a burning sensation in all 4 extremities. Touching the extremities elicited an extreme burning sensation. After in-line stabilization of the cervical spine was performed, palpation of the spinous processes elicited tenderness and an increase in pain. Six weeks before the injury, the athlete had experienced forced lateral flexion of the cervical spine during a match, resulting in an episode of bilateral numbness and burning in his arms. On evaluation by the athletic trainer, symptoms were limited to the right hand, and brachial plexus neurapraxia was diagnosed.
Differential Diagnosis: Central cord syndrome, brachial plexus injury, cervical spine injury, burning hands syndrome, Brown-Séquard syndrome, anterior cord syndrome.
Treatment: Upon assessment, the athlete's cervical spine was immobilized until emergency medical services arrived and applied a cervical collar. Radiographs taken at the hospital revealed a congenital fusion of C6-7. Magnetic resonance imaging and computed tomography showed evidence of stenosis, a herniated disc at C3-4, and a central cord injury. He was admitted to the hospital for observation and was placed on a corticosteroid protocol. At approximately 1 week after the injury, the athlete underwent a cervical decompression and fusion at C3-4. Subsequently, he underwent extensive rehabilitation and has had some persistent neck stiffness. The athlete is no longer allowed to participate in contact sports as a result of the presence of stenosis at multiple levels.
Uniqueness: Central cord syndrome is typically seen in an older population with cervical spondylosis and rarely occurs in young adolescents. However, this athlete sustained 2 central cord injuries, 1 mild and 1 severe, in less than 6 weeks' time.
Conclusions: The original injury sustained by the wrestler was thought to be a brachial plexus injury but, in fact, was a mild central cord injury. Central cord syndrome was not suspected in the original injury because the athlete's complaint was of unilateral numbness. With the second injury, the central cord injury was more severe. Proper recognition, assessment, and handling of this situation were crucial in providing optimal care to this athlete.
spinal cord injury; athletic injury; neurologic injury
The amniotic band syndrome has a scarce prevalence and intrauterine death as a result of amniotic bands formation is extremely rare.
We present an illustrative case of intrauterine death of an embryo in the 24th gestational week in an 30-year old primigravida. The death was ascribed to the twisting of the umbilical cord around the left upper extremity, causing a strangulation of the umbilical cord in a very impressive way.
Constriction of the umbilical cord by an amniotic band is extremely rare and very hard, if not impossible, to diagnose with antenatal sonography.
Patients with cervical spondylotic myelopathy (CSM) have the same clinical symptoms that vary according to the degree of spinal cord compression and the cross-sectional cord shape. We used a three-dimensional finite element method (3D-FEM) to analyze the stress distributions of the spinal cord with neck extension under three cross-sectional cord shapes.
Experimental condition for the 3D-FEM spinal cord, ligamentum flavum, and anterior compression shape (central, lateral, and diffuse types) was established. To simulate neck extension, the spinal cord was extended by 20° and the ligamentum flavum was shifted distally according to movement of the cephalad lamina.
The stress distribution in the spinal cord increased due to invagination of the ligamentum flavum into the neck extension. The range of stress distribution observed for the diffuse type was wider than for the central and lateral types. In addition, the stress distribution in the spinal cord was increased by the pincer movement of the ligamentum flavum and by the anterior compression of the spinal cord. The range of stress distribution observed for the diffuse type under antero-posterior compression was also wider than for the central and lateral types.
This simulation model showed that the clinical symptoms of CSM due to compression of the diffuse type may be stronger than for the central and lateral types. Therefore, careful follow-up is recommended for anterior compression of the spinal cord of diffuse type.
Spinal cord; Morphometry; Cervical spondylotic myelopathy; Finite element method; Ligamentum flavum; Pincer effect; Spinal cord; Anterior compression
Background and Purpose:
Spinal cord toxicity can be dreaded complication while treating head and neck cancer by conventional radiotherapy. Cord sparing approach is applied by two phase planning in conventional head neck radiotherapy. In spite of cord sparing approach spinal cord still receives considerable scatter dose. Our study aims to do the volumetric analysis of spinal cord dosimetry and to correlate with the clinical findings.
Materials and Methods:
Treatment planning was done in two phases. First phase treatment fields include gross disease- both tumor and involved nodes. in the second phase, treatment field shrinkage was done to cover the gross disease sparing the spinal cord. These fields are termed as off-cord fields. 42 patients with histological proven squamous cell carcinoma of the head and neck region were analysed with two groups. In Group A, 46 Gy was given in 23 fractions, and then tumor-boost with off-cord field received 24 Gy in 12 fractions. In Group B 50 Gy was prescribed in 25 fractions initially, then off-cord field given 20 Gy in 10 fractions to analyze theoutcome. Planning Computed tomography (CT) scan was done Philips Brilliance 16 slice CT scan machine, and contouring and dose calculation were done at ASHA treatment planning software.
Maximum dose and dose at 1 cm3, 2 cm3, and 5 cm3 were calculated. Maximum dose to cord was 52.6 Gy (range 48.1-49.7 Gy) in Group A and 54.3 Gy (range 51.48-52.33 Gy) in Group B initially. Off-cord fields received mean dose 8.07 Gy (85.85% of maximum) in Group A and 5.47 Gy (86.84% of maximum) in Group B. At the end of 6 months from the last date of radiotherapy, grade 1 spinal cord toxicity found in two patients in Group A and one patient in Group B respectively (P = 0.55). Both groups received additional dose, which are higher than the prescribed dose, but no patients show significant spinal cord toxicity after 6 month of follow-up.
Spinal cord received scatter dose which much higher than the predicted dose in conventional radiotherapy of head neck cancer. Short term follow up failed to establish clinical correlation with volumetric dose of spinal cord. Two phase cord sparing head neck radiation planning if practiced should be used with caution.
Head neck cancer; off-cord field; spinal cord; volumetric analysis
Cardiovocal syndrome or Ortner's syndrome is hoarseness due to left recurrent laryngeal nerve palsy caused by mechanical affection of the nerve from enlarged cardiovascular structures. Chronic thromboembolic pulmonary hypertension is extremely rarely found to cause this syndrome. We describe a case of a 56-year-old patient with sudden onset of hoarseness. The patient had known long standing severe pulmonary hypertension. Fiberoptic laryngoscopy showed left vocal cord palsy. Computed tomography of the neck and chest revealed extensive enlargement of the pulmonary arteries and excluded a malignant tumor. The diagnosis of cardiovocal syndrome was retained. It is important for the radiologist to be aware of this possible etiology causing left recurrent laryngeal nerve palsy and to understand its mechanism.
The authors describe the case history of a patient who was stabbed in the back of his neck with a knife and who later presented with a Brown-Séquard syndrome attributable to cervical spinal cord damage. Myelography and CT revealed a compressive extradural lesion shown at exploratory operation to be a loculus of cerebrospinal fluid (CSF). The loculus had formed as a consequence of leakage of CSF through a dural tear caused by the knife. Evacuation of this loculus resulted in some neurological improvement. The necessity of obtaining a clear history and of performing a thorough clinical examination is explained. The need to admit patients in whom stab wounds of the neck have transgressed subcutaneous fat is reiterated. Early referral to a neurosurgeon is advised for those patients with neurological deficits.
Klippel-Feil syndrome (KFS) is an unusual skeletal disorder characterized by congenital fusion of two or more cervical vertebrae which can be sporadic or familial. KFS emerges to be a failure of the normal segmentation and fusion of the mesodermal somites during 3rd and 8th weeks of embryonic development. The triad of low posterior hairline, short neck, and restricted neck motion is present only in 50% and often associated with scoliosis, spina bifida, Sprengel's deformity, cervical ribs, deafness, cleft palate, renal anomalies, congenital heart defects, and so on because of heterogeneous nature of the disease. The significance of KFS lies in the secondary effects produced on the nervous system, which usually presents with features of progressive cord and brain stem compression with relatively minor trauma. We here report two cases of KFS presented in association with amyotrophic lateral sclerosis. Only two such cases have been described in the literature in 1954 and 1975.
Amyotrophic lateral sclerosis; bone morphogenetic protein; Klippel-Feil syndrome; Pax-1; sonic hedgehog
Atlantoaxial instability (AAI) affects 10–20% of individuals with Down syndrome (DS). The condition is mostly asymptomatic and diagnosed on radiography by an enlarged anterior atlanto-odontoid distance. Symptomatic AAI, which affects 1–2% of individuals with DS, manifests with spinal cord compression. Cervical spondylosis, which is common in DS, also has the potential for cord damage but it has received less attention because paediatric populations were mostly studied. Forty-four Kuwaiti subjects with DS, whose ages were ≥15 years, were evaluated clinically and radiographically. Lateral neck radiographs were taken in the neutral and flexion positions. Asymptomatic AAI was diagnosed in eight subjects (18%) and congenital anomalies of C1–2 were found in five (12%). Five patients had AAI in flexion only while three patients had it in both views. Three patients with AAI had odontoid anomalies contributing to the condition. When assessing AAI, the posterior atlanto-odontoid distance has to be considered because it indicates the space available for the cord. Cervical spondylosis was noted in 16 (36%) subjects. Degenerative changes increased with age, occurred earlier than in the normal population, and affected mostly the lower cervical levels. Half the patients with AAI had cervical spondylosis, a comorbidity that puts the cord at increased risk.
Craniovertebral junction (CVJ) tuberculosis is a rare disease, potentially causing severe instability and neurological deficits. The authors present a case of CVJ tuberculosis with atlantoaxial dislocation and retropharyngeal abscess in a 28-year-old man with neck pain and quadriparesis. Radiological evaluations showed a widespread extradural lesion around the clivus, C1, and C2. Two stage operations with transoral decompression and posterior occipitocervical fusion were performed. The pathological findings confirmed the diagnosis of tuberculosis. Treatment options in CVJ tuberculosis are controversial without well-defined guidelines. But radical operation (anterior decompression and posterior fusion and fixation) is necessary in patient with neurological deficit due to cord compression, extensive bone destruction, and instability or dislocation. The diagnosis and treatment options are discussed.
Tuberculosis; Craniovertebral junction; Atlantoaxial dislocation; Retropharyngeal abscess
Background. Lhermitte's sign (LS) is a benign form of myelopathy with neck flexion producing an unpleasant electric-shock sensation radiating down the extremities. Although rare, it can occur after head and neck radiotherapy. Results. We report a case of Lhermitte's developing after curative intensity-modulated radiotherapy (IMRT) for a patient with locoregionally advanced oropharyngeal cancer. IMRT delivers a conformal dose of radiation in head and neck cancer resulting in a gradient of radiation dose throughout the spinal cord. Using IMRT, more dose is delivered to the anterior spinal cord than the posterior cord. Conclusions. Lhermitte's sign can develop after IMRT for head and neck cancer. We propose an anterior spinal cord structure, the spinothalamic tract to be the target of IMRT-caused LS.
Superficial haemosiderosis results from chronic subarachnoid haemorrhage during which haemosiderin is deposited in the leptomeninges around the brain, spinal cord and cranial nerves. We describe an exceptional case of superficial haemosiderosis characterised by two special aspects. (1) The cause was a secondary tethered cord syndrome due to dural adhesions which had developed 8 years after resection of a thoracic lymphoma and (2) an explorative neurosurgical procedure with complete untethering caused normalisation of the cerebrospinal fluid and stopped disease progression.
Devic's neuromyelitis optica is an inflammatory demyelinating disease that targets the optic nerves and spinal cord. It has a worldwide distribution and distinctive features that distinguish it from multiple sclerosis. There has been no previous report of neuromyelitis optica from our practice environment, and we are not aware of any case associated with antiphospholipid syndrome in an African person.
We report the case of a 28-year-old Nigerian woman who presented with neck pain, paroxysmal tonic spasms, a positive Lhermitte's sign and spastic quadriplegia. She later developed bilateral optic neuritis and had clinical and biochemical features of antiphospholipid syndrome. Her initial magnetic resonance imaging showed a central linear hyperintense focus in the intramedullary portion of C2 to C4. Repeat magnetic resonance imaging after treatment revealed resolution of the signal intensity noticed earlier.
Neuromyelitis optica should be considered in the differential diagnoses of acute myelopathy in Africans. We also highlight the unusual association with antiphospholipid syndrome. Physicians should screen such patients for autoimmune disorders.
Morquio-Brailsford syndrome is a type of mucopolysaccharidoses. It is a rare disease with features of short stature, atlantoaxial instability with risk of cord damage, odontoid hypoplasia, pectus carinatum, spine deformities, hepatomegaly, and restrictive lung disease. Neck movements during intubation are associated with the risk of quadriparesis due to cervical instability. This, along with the distortion of the airway anatomy due to deposition of mucopolysaccharides makes airway management arduous. We present our experience in management of difficult airway in a 3-year-old girl with Morquio-Brailsford syndrome posted for magnetic resonance imaging and computerized tomography scan of a suspected unstable cervical spine. As utmost sagacity during intubation is required, the child was intubated inside operation theatre in the presence of experienced anesthesiologists and then shifted to the peripheral location. Intubation was done with an endotracheal tube railroaded over a pediatric fibreoptic bronchoscope passed through the lumen of a classic laryngeal mask airway, keeping head in neutral position.
Cervical instability; classic laryngeal mask airway; cord damage; difficult airway
The syndrome of 'benign thoracic pain' is seen in young women who have pain and tenderness in the mid-thoracic spine radiating around the chest and aggravated by spinal movement. Ten consecutive patients with this syndrome and 15 controls were evaluated with magnetic resonance imaging (MRI). This showed thoracic intervertebral disc dehydration with no associated prolapse in 90% of the patients and 13% of the controls. We postulate that the clinical features are due to impaired shock absorption of these degenerate discs rather than direct compression of surrounding structures. MRI is non-invasive and does not use ionizing radiation; it allows direct visualization of the entire thoracic spine and cord, and accurate detection of early disc degeneration. Thus, it is the imaging modality of choice for defining the subtle intervertebral disc abnormalities that characterize the 'benign thoracic pain' syndrome.
The cervical spine, usually regarded as a supporting structure for the head, is also an important viaduct of vessels and nerves which must function with little clearance in a congested and moving space bounded by bone. Pressure in this viaduct is an important cause of headache.
The cervical foramina although apparently roomy, are constricted by cartilage, by the vertebral artery and its adnexae, and by the lateral intervertebral joints. Osteophytosis, swelling or adhesion in this constricted space almost inevitably causes painful vascular or neural disorder.
In certain postures of the neck the vertebral artery is constricted or even occluded. Traction or sprain may likewise cause headache through disturbance of the vertebral arterial nerves, the posterior cervical autonomic system or the spinal accessory nerves which originate in delicate filaments from all points of the cervical spinal cord.
A syndrome described by Skillern—migraine-like suboccipital and retro-orbital headache—is due to disturbance of the second cervical nerve, which communicates with the first division of the trigeminal nerve.
Headache due apparently to a minor scalp contusion may really be due to irritation of a trigger area at the site of an old scalp injury.
Radiography of the lateral neck was performed on all children with Down's syndrome aged 4-15 in the Southern Derbyshire health district (n = 67) and a random selection of adults (n = 94). Atlantoaxial instability, defined as a gap of over 4 mm, was present in seven (10%) children and two (2%) adults. Odontoid hypoplasia, defined as an odontoid peg two standard deviations below the mean in an age matched population, was present in 15 (22%) children and 14 (15%) adults, with accessory odontoid ossicles present in two (2%) and two (3%) respectively. No one was found to have symptoms or clinical signs of spinal cord compression. Atlantoaxial instability was therefore found to be commoner in children than adults. Different programmes of management are suggested, in terms of regular clinical examination for signs and symptoms and by radiographic screening. Particular care should be taken with those who have both atlantoaxial instability and odontoid hypoplasia or accessory ossicles as they are at particular risk of spinal cord damage.
Cervical spondylosis is a broad term which describes the age related chronic disc degeneration, which can also affect the cervical vertebrae, the facet and other joints and their associated soft tissue supports. Evidence of spondylitic change is frequently found in many asymptomatic adults. Radiculopathy is a result of intervertebral foramina narrowing. Narrowing of the spinal canal can result in spinal cord compression, ultimately resulting in cervical spondylosis myelopathy. This review article examines the current literature in relation to the cervical spondylosis and describes the three clinical syndromes of axial neck pain, cervical radiculopathy and cervical myelopathy
Flexion myelopathy is one of the suggested mechanism for Hirayama disease (HD) but simultaneous radiological and neurophysiological evaluation is lacking. This study therefore evaluates the effect of neck flexion in HD using somatosensory evoked potentials (SEPs), F waves, and magnetic resonance imaging (MRI).
Eight HD patients and seven matched controls were subjected to median and ulnar F wave (minimal latency, FM ratio, persistence, and chronodispersion), and SEPs evaluating N9, N13, and N20 potentials in neutral and neck flexion. Spinal MRI was carried out in neutral and neck flexion and evaluated for cord atrophy, signal changes, cord compression, posterior epidural tissue, and loss of dural attachment.
The patients were aged 19 to 30 years. Minimal F latency, FM ratio, persistence, and chronodispersion in neutral and neck flexion did not show any change nor was there any change in N13 latency and amplitude on median and ulnar SEPs. The difference in these parameters in neutral and neck flexion were also not significant in HD compared with controls. The change in N13 was also not related to loss of dural attachment and posterior epidural tissue.
Neck flexion does not produce significant changes in N13 and F wave parameters and is not related to dynamic MRI changes. The other mechanisms for HD should therefore be explored.
F wave; Hirayama disease; magnetic resonance imaging; somatosensory evoked potential; neck flexion