Intramedullary spinal cord Tumors

Intramedullary tumors are the tumors which are present in the spinal cord, i.e., inside the pial covering and substance of the spinal cord itself.

This diagram explains the location of the intramedullay tumors. Piamater is the innermost of three meninges ( Duramater, Arachnoid and Piamater). It covers the spinal cord. So the tumors outside of it may be IDEM ( intradural extramedullary) or extradural lesions. 

Spinal tumors are are classified as

 (1) extradural,

(2) intradural extramedullary, and

 (3) intradural intramedullary.

Extradural tumors are the most common spinal tumors and are usually of metastatic origin. 

Intradural Extramedullary (IDEM) tumors are mainly neurofibroma and meningioma.

Intradural intramedullary lesions comprise 20 to 30% of all primary spinal cord tumors.

Gliomas make up 80% of all intramedullary tumors. The gliomas are further subdivided into astrocytomas (60 to 70%) and ependymomas (30 to 40%). Hemangioblastomas are the third most frequent intramedullary spinal cord (IMSC) tumors, comprising 2 to 15% of all intramedullary tumors. Metastatic intramedullary tumors are rare but present in 2% of all intramedullary tumors. Lipomas are commonly associated with spinal dysraphism.

Intramedullary tumors constitute about 35-40% of all intraspinal tumors in children. In children intramedullary tumors are mainly developmental in origin, like dermoid, lipoma and epidermoid). In adults intramedullary tumors may arise later in life, like astrocytoma, ependymoma and hemangioblastoma.

Gliomatous and nongliomatous tumors constitute 90 and 10% respectively.

In 75% cases, the astrocytmas extend over 4 or less 4 vertebral segments. In some cases the lesions extends throughout the spinal cord, for example holocord astrocytomas.

Half of the central nervous system ependymomas are located in the spinal cord and, of these, 50% are located in the filum terminale. The next common site is the cervical cord.

Glioblastomas are not common.

Hemangioblastoms are rare, consist of less than 2% of primary spinal cord tumors.

Clinical presentation depends upon the site and size of the lesion.

MRI of spine with contrast is the investigation of choice.

                                  Intraoperative image of my adult patient where tumor is seen after posterior midline myelotomy. Histopathology of the tumor was suggestive of Pilocytic astrocytoma ( WHO grade 1 tumor)

The operating microscope, bipolar coagulators, intraoperative physiological monitoring ( somatosensory evoked potenial monitoring, motor evoked potential ) , microscissors, microdissectors, small tumor holding forceps, Cavitron Ultrasonic Surgical Aspirators (CUSA) , intraoperative USG ( Ultrasonography) are good for safe excision of intramedullary lesions.

References

Samartzis D, Gillis CC, Shih P, O'Toole JE, Fessler RG. Intramedullary Spinal Cord Tumors: Part I-Epidemiology, Pathophysiology, and Diagnosis. Global Spine J. 2015;5(5):425-35. And references as numbered below

Mechtler L L, Nandigam K. Spinal cord tumors: new views and future directions. Neurol Clin. 2013;31(1):241–268.

Grimm S, Chamberlain M C. Adult primary spinal cord tumors. Expert Rev Neurother. 2009;9(10):1487–1495.

DeSousa A L, Kalsbeck J E, Mealey J Jr, Campbell R L, Hockey A. Intraspinal tumors in children. A review of 81 cases. J Neurosurg. 1979;51(4):437–445.

Mandigo C E, Ogden A T, Angevine P D, McCormick P C. Operative management of spinal hemangioblastoma. Neurosurgery. 2009;65(6):1166–1177.

Ravi Ramamurthy. Spinal Intramedullary Tumours. Chapter 130, Volume 2, in Textbook of Operative Neurosurgery, B.I Publications Tvt Ltd, New Delhi, Pages1107-1113.

Surgical cases of Tuberculosis of Central Nervous System

Tubercuolosis (TB) continues to be a major public health concern, especially in developing countries. TB is one of the top 10 causes of death worldwide . In 2016, 10.4 million people fell ill with TB; and 1.7 million died from the disease. In 2016, an estimated 1 million children became ill with TB and 250,000 children died of TB. 
Tuberculosis of central nervous system (CNS) can be treated effectively with anti-tubercular therapy (ATT). ATT duration for treatment of CNS TB is 12 months ( 2 months intensive phase and 10 months continuation phase). Some cases of CNS TB require neurosurgical intervention. I am presenting 3 cases of cranial TB where the presentations were unusual leading to delay in the diagnosis. All these three cases were effectively treated with neurosurgery along with ATT.

Patient 1 was a middle aged female with history of headace of long duration. CT scan of head revealed extradural collection beneath the frontal bone. The frontal bone was thickened. This was unusual as duration of symptom was in years and the bone above the lesion was thickened.

 Surgical image showing  pus coming out of frontal bone bur hole

As intensity of the headadche increased , patient was advised surgery. On craniectomy about 60 ml of pus came out under pressure. Patient became asymptomatic after surgery and ATT.

Patient 2 was a middle aged male with history of trauma and swelling over the vertex of skull about 15 days back. Patient was suspected to have scalp hematoma and swelling and was advised antibiotics and analgesics. CT scan showed a scalp swelling over the cranium. Patient underwent surgery and about 40 mL of pus was drained and it was sent for culture/ sensititivity, Gram stain , AFB stain. It came out positive for Staphylococcus. But, despite of prescribing antibiotic according to sensitivity, wound was not healing. Later, wound was re-explored and remaining pus drained out and bony osteomyelitis of the cranium was evident. Craniectomy of the pariental bone at the vertex was done and sent for histopathological examination. Biopsy was suggestive of tuberculosis.

                                                  Surgical image of the patient showing calvarial osteomyelitis

Patient's surgical wound healed with antibiotic and ATT. He became asymtomatic after taking ATT.

Patient 3 was a child of about 14 year age. He presented in emergency of my Institute with history of headache, vomiting, deterioration of conscious level, weakness of right half of body and recurrent seizures. CT scan of the brain and MRI of brain with contrast revealed intracranial subdural hypodense collections in interhemispheric fissure and left fronto-parietal convexity of brain.

                         Surgical image showing burr hole in the frontal bone and pus coming out of subdural space
Frontal region incision was made and single burr hole made in frontal bone under general anesthesisa. Dura was coagulated and incision made in dura. About 80 mL of thick pus came out under pressure. Patient improved after surgery and ATT.

Many types of neurotuberculosis have been described; most common intracranial forms are tuberculous meningitis and tuberculomas.Tuberculous brain abscess and subdural empyema are extremely rare manifestations of central nervous system tuberculosis. Subdural empyema or collection of pus in the subdural space is mostly pyogenic.  Intracranial tubercular subdural empyema is very rare in pediatric population. Various  diagnostic  modalities  and  treatment options  are  available  for  managing central nervous system tuberculosis (CNS  TB).   But, outcome  remains of CNS TB is poor as clinicians  face  many challenges  in  the  management  of  the  tubercular infection  of  the  brain  and  spinal cord.

Treatment of CNS TB is challenging due to lack of specific biochemical tests and inability to get the pathological sample from deeply located eloquent areas of CNS without causing any neurological deficit. Moreover, it is unnecessary to operate for biopsy in a patient who has presented with a very small granulomatious lesion in brain or spinal cord. In such as situations neuro-radiology helps in managing CNS TB and it may be the only source of establishing diagnosis and evaluating treatment response. Role of radiological investigation has expanded from the initial diagnosis to the therapeutic interventions. In some Muli-drug- resistant (MDR) CNS TB cases, stereotaxy or Ultrasonogram (USG) or CT guided biopsy helps in obtaining pathological sample and drug sensitivity testing. A regular clinical and neuro-radiological follow-up is mandatory during the entire course of anti tuberculous therapy to take prompt decisions to change ATT and to reduce morbidity and mortality associated with CNS TB.

Traditionally, culture for the mycobacterium is considered as gold standard for diagnosis of TB. But,  tuberculin  test,  biochemical  investigations and  AFB  stain  and  culture  of  the  cerebrospinal fluid  or  granulation  tissue  provide  little  support for the management of CNS TB or its sequelae.  There should be high index of suspicion for the CNS TB in a patient who is from an endemic region. There may be extensive tubercular involvement of CNS even  in  absence  of  the  history of pulmonary diseases,  tubercular  contact  or  any  other neurological  deficit.  It is difficult  to assess  the therapeutic response in the early follow up period in view of the lack of sensitive and specific tests. Vigilant clinical observation and imaging studies is required in the early follow up period to identify the  worsening  or  new  emerging  signs  in  the patients  of  CNS  TB.  Imaging  studies  are becoming  the  major  decisive  tools  for  the empirical  therapy  and  early  follow  up  of  the patients to evaluate the therapy.

Intracranial tubercular subdural empyema can be effectively treated with ATT and burr hole evacuation of pus. Close clinical observation, neuroradiological assessment with CT scan or MRI and prompt therapeutic interventions   are  necessary  for starting the empirical anti-tuberculous  therapy and early follow up of the patients to evaluate the therapeutic response. 

 In all these cases pus was negative for Acid Fast Bacillus (AFB). This is very common observation. So, high index of suspicion and close follow up is required in suspected cases of cranial TB. Clinical observation with empirical ATT is key in the management of CNS TB cases.

References

1.       An unusual presentation of neurotuberculosis: subdural empyema . Case report. Cayli SR, Onal C, Kocak A, Onmus SH, Tekinen A. J Neurosurg 2001 Jun; 94(6): 988-91

2.       Global tuberculosis report 2017, WHO ( www.who.int)

3.       Pediatric intracranial subdural empyema caused by Mycobacterium tuberculosis- a case report and review of literature. Banerjee AD, Pandey P, Ambekar S, Chandramouli BA. Child Nerv System. 2010, Aug: 26(8): 117-20.doi 10.1007/s00381-010-1157-3 Epub 2010 May 2

4.       Intracranial tuberculous subdural empyema: case report. Van Dellen A, Nadvi  SS, Nathoo N, Ramdial PK. Neurosurgery 1998, Aug; 43(2), 370-3.

5.        Vijaykumar B, Sarin K, Girija Mohan. Tuberculous brain abscess and subdural empyema in an immunocompetent child: Significance of AFB staining in aspirated pus. Ann Indian Acad Neurol. 2012, Apr-Jun, 15(2):130-133.

6.       Gautam VKS, Khurana S & Singh R. Diagnostic and therapeutic challenges in the surgical management of CNS tuberculosis. International Journal of Medicine and Health Sciences, 2013, Vol-2;Issue-2, 161-169. 

Concussion

Concussion means transient loss of consciousness due to head injury.
Concussion is also known as Mild Traumatic Brain Injury (MTBI). 
It may be described as alteration of consciousness without structural damage as a result of head trauma. 

It is transient loss of consciousness or alteration in mental status like alteration in conscious level,  disturbance of vision or balance due to head injury.

Trauma to the head may cause sudden linear or rotational movement of the brain.  This sudden acceleration and deacceleration  movements of the brain and brain stem disrupts the normal cellular activities in the brain ( including fornix, corpus callosum, temporal lobe, frontal lobe) and in the the reticular activating system of the midbrain.  

Although, concussion is considered as mild head injury but sometimes it has sequelae. Headache, confusion, amnesia, blurring of vision, dizziness, fatigue  may persist for some time.  More alarming long term sequelae are the cognitive impairment, sleeplessness, difficulty in concentration,  irritability, anger, behavioural abnormalities, or maladjustment in the work or studies.

Plain CT scan of brain is the investigation of choice. It is normal in cases of concussion because it is a physiological impairment and so, no anatomical abnormality is seen on non-contrast CT scan of the brain. MRI of the brain is not required and  is unnecessary. MRI will demonstrate abnormalities in up to 25% of cases where CT is normal. But, I do not suggest MRI in cases of concussion because CT actually guides the treatment. So, if CT is normal there is nothing serious and no active neurosurgical treatment is required. MRI just adds to the apprehension of the patients and their relatives and it does not provide any additional information of any use to the neurosurgeon.

Symptoms usually resolve in approximately two weeks. But, symptoms may persist for longer period.

Every person with post traumatic concussion requires emotional support. 
Patient’s caregivers, family members, teachers and co-workers and colleagues must understand that some symptoms like irritability, headache, dizziness may be sequelae of concussion.  So,  a sympathetic and considerate attitude should be adopted towards the person who had suffered mild head injury with concussion and is experiencing long term sequelae of mild head injury. 
Symptomatic treatment of like dizziness may be trated with Betahistine or Cinnarazine. Headache is a common complaint and requires both medical and psychological support.
Neurotrophic vitamins like vitamin B complex, Methylcobalamin,  vitamin E are useful.  Anxiety, sleeplessness are very well managed with tablet Clonazepam 0.25 mg at night and Psychological support.

Spina Bifida, Spinal Dysraphism, Myelomeningocele and Meningocele

Spinal dysraphism means a spectrum of congenital anomalies of the spine and spinal cord.

Spina bifida is a common form of spinal dysraphism. The term spina bifida includes a wide variety of anomalies.
  
Congenital defect in the spine leads to spina bifida. This can be of two types: spina bifida occulta and spina bifida aperta.

In spina bifida aperta; visible lesion, like a swelling over the midline of the back may be noticed at the time of birth of a child. Such spinal dysraphism is known as Spinal Bifida Aperta.

But, a child may be having some abnormalty of the spine or spinal cord but without any externally visible lesion and overlying skin is intact, then it is known as Spina Bifida Occulta.  This defect of the vertebrae of the spine of a child may not be visible at the time of birth and there may be no visible exposure of meninges or neural tissue. And, there may be congenital defect only in the lamina of the vertebrae of the spine without any involvement of underlying spinal cord. This is known as spine bifida occulta.

But, in spina bifida aperta there is a visible or open defect in the spine. There may be congenital defect in vertebral arches with cystic distension of meninges which is filled with CSF and is known as Meningocele. If, in this congenital defect of the vertebral arches there is a cystic dilatation of meninges and cerebrospinal fluid along with neural tissue or spinal cord ( Myelon) , then it is known as Myelomeningocele. If Myelomengocele contains fat tissue, then it is known as Lipomyelomengocele.

Myelmeningocele is one of the congenital open neral tube defect present at the birth on the back of the newborn.

It is a common type of congental defect of the spine and its incidence is about 1 in 1,000 live births. Better nutrition and folic acid suplementatiion during the antenatal care of the mother decrease its occurrence.

Ultrasound study during the early antenatal care detects any occurrence of myelomeningocele in a fetus during pregnancy.

A newborn child should be assessed for any sensory or motor deficit due to meningocele or myelomeningocele. There may be associated congenital lesions, like cardiac lesions. Myelomeningocele may be associated with congenital hydrocephalus. So, MRI of the spinal cord and brain is investigation for choice for assessing a case of meningcele. MRI may show whether a swelling on the back of a child is only flled with CSF or does it contain any neural tissue. It detects any intraspinal extension, associated intrasinal dermoid, lipoma, dermal sinus, spina bifida, spinal dysrahism like duplication of the cord, any bony spur between the duplicated cord, Chiari malfomation, syrinx, hydrocephalus, thickened filum terminale, etc. So, MRI helps in diagnosis, surgical planning and predicting prognostic outcome.
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