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Background Hospital-based cancer registries can provide information on the magnitude and distribution of cancers in a given hospital. Hospital-based brain tumor registry data, focusing on glioma, from a tertiary care rural neurological center is lacking in the scientific literature. This data can be useful in understanding the need for research and funding required for these specific brain tumors. Data of patients operated for glioma, at our institute, was collected between January 2004 and December 2015. Patients’ clinical details and histopathological diagnosis were recorded. Data were analyzed and compared with that of previously published literature, and inferences were drawn on patterns of reporting and epidemiology. Results A total of 1450 cases of glioma, with a mean age of 39.3 (± 17.36 SD) years with males (66.6%) comprising more population as compared to females. Majority of patients 70.8% (n = 1027) belong to the economically active age group of country (18–60 years). Majority of cases (41.4%) were glioblastoma with the next common tumor (22.8%) being diffuse astrocytoma (n = 331) followed by pilocytic astrocytoma (6.2%) and oligodendroglioma (4.5%) in that order. While our data followed similar trends with other Indian data the average age of glioma was a decade younger to what is quoted earlier in Indian and international studies. Conclusion This data for glioma gives a glimpse of the prevalence of this tumor in a primarily rural population and highlights the need for a National Brain Tumor Registry with the need for the development of evidence-based policymaking and enhanced research into this particular ailment.

Leptomeningeal cysts are commonly seen in children usually following trauma and associated with bulging leptomeninges at the site of fracture. Intradiploic leptomeningeal cyst is an important differential for an expansile lytic lesion in the bony calvarium especially in a patient with a previous history of trauma. Here we present a case of intradiploic leptomeningeal cyst and describe the usefulness of retrograde cisternogram by CT-guided direct percutaneous cyst puncture where a CT cisternogram after intrathecal contrast injection could not demonstrate the dural defect and communication of the subarachnoid space with the intradiploic leptomeningeal cyst.

Neurenteric cysts (NC) occur due to failure of separation of neurectoderm from endoderm at the 3rd week of embryogenesis. This study focuses on key clinico-radiological features of NCs, with emphasis on surgical nuances involved in resecting anteriorly placed NC, especially at the foramen magnum (FM). Sixteen consecutive patients having a spinal NC were included. Their clinico-radiological status, surgical nuances and follow-up status were noted. The duration of spasticity/paraparesis/quadriparesis ranged from 15 days to 48 months. Twelve patients had an intradural extramedullary (IDEM; nine anterior and three anterolateral) cyst and four had an intramedullary (IM) cyst. Six of them had an anteriorly placed FM lesion (five IDEM and one IM). Amongst ten subaxial NCs, four were anterior, two antero-lateral and one postero-lateral; three were IM. Three patients had the characteristic stigmata of occult spinal dysraphism: two, a large mesenteric cyst, and one, a posterior mediastinal cyst. Excision was total in 13 patients. Subtotal excision of tumour capsule was performed for two recurrent cysts and an IM cyst. A far lateral approach was adopted for anteriorly placed FM lesions and posterior laminectomy for subaxial lesions. Histopathology revealed eight type A cysts, four type B cysts and four type C cysts. At follow-up (range, 8 months to 12 years; median, 60 ± 45.84 months), complete neurological recovery occurred in seven patients; six patients had persistent spasticity but only minor disability; two patients had difficulty in walking; and one patient with an anteriorly placed thoracic recurrent NC had sustained neurological deterioration. Surgical difficulties in addressing NCs are related to their anterior or IM location, presence of adhesions and inability to dissect the tumour capsule from the spinal cord due to fibrous or lipomatous connections. The associated developmental anomalies must be specifically sought and addressed.

Giant cell granuloma is a rare benign granulomatous lesion of the bone. The local aggressiveness, potentiation with trauma and complex anatomy of the skull base makes the surgical management in this location challenging. We report a series of three cases along with the clinical presentation, radiological and histopathological findings and the management issues while dealing with this lesion. A review of literature reveals the rarity of the lesion, alternate management modalities and the outcomes for such lesion involving the jaw bones and the skull base. For best outcomes differential diagnosis from giant cell tumor and brown tumor of hyperparathyroidism is essential. Further it may be concluded that there is a need for maximal surgical excision to avoid recurrence as the second line management options are not as effective.

This prospective study attempts to study the clinico-radiological differences between patients with syndromic AAD (SAAD), non-syndromic AAD (NSAAD), and AAD with Klippel-Feil anomaly (AADKFA) that may impact management.In 46 patients with AAD [SAAD (including Morquio, Down, Larson and Marshall syndrome and achondroplasia; n = 6); NSAAD(n = 20); and, AADKFS (n = 20)], myelopathy was graded as mild (n = 17, 37 %), moderate (15, 32.5 %) or severe (14, 30.5 %) based on Japanese Orthopaedic Association Score modified for Indian patients (mJOAS). Basilar invagination (BI), basal angle, odontoid hypoplasia, facet-joint angle, effective canal diameter, Ishihara curvature index, and angle of retroversion of odontoid and vertebral artery (VA) variations were also studied.Clinico-radiological differences were assessed by Fisher's exact test, and mean craniometric values by Kruskal-Wallis test (p value ≤ 0.05 significant)Incidence of irreducible AAD in SAAD (n = 0), NSA AD (11.55 %) and AADKFS (n = 18.90 %) showed significant difference (p = 0.01). High incidence of kyphoscoliosis (83 %) and odontoid hypoplasia (83 %) in SAAD, and assimilated atlas and BI in NSAAD and AADKFA groups were found. In AADKFA, effective canal diameter was significantly reduced(p = 0.017) with increased Ishihara index and increased angle of odontoid retroversion; 61 % patients had VA variations. Thirty-five patients underwent single-stage transoral decompression with posterior fusion (for irreducible AAD) or direct posterior stabilization (for reducible AAD). Postoperative mJOAS evaluation often revealed persistent residual myelopathy despite clinical improvement.Myelopathy is induced by recurrent cord trauma due to reducible AAD in SAAD, and compromised cervicomedullary canal diameter in NSAAD and AADKFA. SAAD in children may be missed due to incomplete odontoid ossification or coexisting angular deformities. In AADKFA, decisions regarding vertebral levels to be included in posterior stabilization should take into consideration intact intervening motion segments and compensatory cervical hyperlordosis. Following VA injury, endovascular primary vessel occlusion/stenting across pseudoaneurysm preempts delayed rehemorrhage.

Accurate grading of cerebral glioma using conventional structural imaging techniques remains challenging due to the relatively poor sensitivity and specificity of these methods. The purpose of this study was to evaluate the relative sensitivity and specificity of structural magnetic resonance imaging and MR measurements of perfusion, diffusion, and whole-brain spectroscopic parameters for glioma grading. Fifty-six patients with radiologically suspected untreated glioma were studied with T1- and T2-weighted MR imaging, dynamic contrast-enhanced MR imaging, diffusion tensor imaging, and volumetric whole-brain MR spectroscopic imaging. Receiver-operating characteristic analysis was performed using the relative cerebral blood volume (rCBV), apparent diffusion coefficient, fractional anisotropy, and multiple spectroscopic parameters to determine optimum thresholds for tumor grading and to obtain the sensitivity, specificity, and positive and negative predictive values for identifying high-grade gliomas. Logistic regression was performed to analyze all the parameters together. The rCBV individually classified glioma as low and high grade with a sensitivity and specificity of 100 and 88 %, respectively, based on a threshold value of 3.34. On combining all parameters under consideration, the classification was achieved with 2 % error and sensitivity and specificity of 100 and 96 %, respectively. Individually, CBV measurement provides the greatest diagnostic performance for predicting glioma grade; however, the most accurate classification can be achieved by combining all of the imaging parameters.

Hyperproteinorrhachia associated with vestibular schwannomas (VSs) may influence visual status independent of the effect caused by raised intracranial pressure. The role of cisterna magna CSF protein levels (CMCP) in determining visual outcome in patients with large to giant vestibular schwannomas (VSs) was prospectively investigated.The mean CMCP levels in VSs and control group; and, levels in VSs with or without visual deterioration were compared. Spearman's rank correlation coefficient tested for relationships between CMCP level with symptom duration and tumour volume (Kawamoto's method). Vision was regarded as normal when visual acuity was6/18; and, deteriorated when it was between 6/18 and PL negative in the worse eye. Papilloedema (n = 26)/secondary optic atrophy (n = 6) and hydrocephalus (based on Evan's ratio, mild to moderate: n = 22; none: n = 18) were also recorded. The analysis of factors predicting diminished vision was done using logistic regression analysis (p 0.05 significant).There was a significant difference (p 0.001) in mean CMCP levels between VS (456.3 SD 213.6 mg/dl) and control groups (96.3 SD 74.3 mg/dl). The mean CMCP levels in the VS group were also markedly higher than the ventricular mean protein levels. The CMCP levels in patients with visual diminution (6/18 to PL negative; n = 23) was 561.4 SD 186.9 mg/dl and those without visual loss (n = 17) was 314.2 SD 160.8 mg/dl (p 0.001). Their grade of visual diminution had a positive correlation with mean CMCP levels (p 0.001). There was a negative correlation between total duration of symptoms and CMCP levels (p 0.015). Logistic regression analysis using five independent factors (symptom duration, papilloedema/secondary optic atrophy, tumour volume, hydrocephalus and mean CMCP level) revealed that only CMCP level had a significant association with visual diminution.Elevated cisternal CSF proteins may play an important role in determining visual outcome in large to giant VSs. Ventricular CSF analysis is often unable confirm the presence of VS-associated cisternal hyperproteinorrhachia. High CMCP levels may influence decision-making while instituting a permanent CSF diversion for postoperative hydrocephalus or recalcitrant pseudomeningocoele.

Spina bifida cystica (SBC) is a group of neurodevelopmental defects caused by improper neural tube closure, which may be responsible for deficits in cognitive functions. The purpose of this study was to examine changes in normal appearing deep gray and white matter brain regions in SBC patients compared with controls through diffusion tensor imaging (DTI) and correlate these changes with neuropsychometric tests. Conventional magnetic resonance imaging and neuropsychometric tests were performed on 13 patients and ten controls. DTI-derived fractional anisotropy (FA) and mean diffusivity (MD) were quantified in different brain regions in controls and patients. Significantly decreased FA was observed in caudate nuclei, putamen, genu, splenium, and increased FA was found in middle cerebellar peduncle (MCP) in patients compared with controls. We observed significantly increased MD in genu and splenium. However, increased MD was found in fornix of patients compared with controls. Majority of neuropsychological tests were found to be significantly impaired and some of these showed significant correlation with DTI metrics in genu, splenium, and MCP in these patients. We conclude that DTI metrics are significantly abnormal in deep gray matter nuclei, genu, splenium, and MCP in SBC patients and may provide microstructural basis for neuropsychological abnormalities in these patients.

Background: Os odontoideum (OO) with C1-2 anterolisthesis and retrolisthesis may cause cervicomedullary injury both from anterior and posterior aspects. We analyzed fourteen such patients for biomechanical issues, radiological features and management of OO with free-floating atlantal arch and review pertinent literature. Materials and Methods: Fourteen patients having nonsyndromic, reducible atlantoaxial dislocation (AAD) with orthotopic OO were analyzed. During neck flexion, their C1 anterior arch-os complex displaced anteriorly relative to remnant odontoid-C2 body. The posteriorly directed hypoplastic remnant odontoid sliding below the atlas and forward translation of the C1 posterior arch caused concomitant cervicomedullary compression. During neck extension, there was retrolisthesis of the “free-floating” C1 arch-os complex into spinal canal. Spinal stenosis and lateral C1-2 facet dislocation; Klippel-Feil anomaly; and posterior circulation infarcts were also present in one patient each, respectively. Posterior C1-2 (n=10) or occipitocervical fusion (n=3) was performed in neutral position to stabilize atlantoaxial movements. Results: Follow-up (mean, 3.9 years) assessment revealed improvement in spasticity and weakness in 13 patients. One patient had neurological deterioration following C1-2 posterior sublaminar fusion, requiring its conversion to occipitocervical contoured rod fusion. One patient with posterior circulation stroke died prior to any operative intervention. Follow-up lateral view radiographs showed a bony union or a stable construct in these 13 patients. Conclusions: OO with free-floating atlantal arch may precipitate cord injury both during neck flexion and extension. This condition may be overlooked unless lateral radiographs of craniovertebral junction are undertaken in neck extension, along with the usual ones in neutral and flexed positions. Etiological factors include C1 ring-OO unrestrained movements above the hypoplastic odontoid; upward pull on OO by alar and apical ligaments; lax C1-2 facet joint ligaments; and congenital presence of horizontal facet joint surfaces that facilitates C1-2 translation.

Pediatric colloid cysts (CC) have a congenital origin, and yet, there are very few studies focussing exclusively on their occurrence in the pediatric population. Pediatric CC has been associated with more aggressive clinical and radiological patterns than their adult counterparts. In this study, undertaken on children with anterior third ventricular CC, excised using the interhemispheric transcallosal approach, the characteristic clinicoradiological features and management options are studied. Five pediatric patients (aged 16 years or less; mean age 13.8 years; mean duration of symptoms:7.6 months) out of 38 patients with CC operated between 1995 to 2009 were included. The clinical manifestations included those of raised intracranial pressure (n = 4); exacerbation of occipital headache on reading (n = 1); secondary optic atrophy (n = 3); and, drop attacks (n = 1). On computed tomography scan, the cyst was hyperdense, enhancing in two patients and not enhancing in three patients. All had bilateral lateral ventricular dilatation with periventricular lucency. On magnetic resonance imaging (n = 3), the cyst was T1 hypointense and T2 isointense in one, hyperintense on both T1 and T2 with a hypointense capsule and nonenhancing on contrast in one (with a giant colloid cyst), and T1 hyperintense and T2 hypointense in one patient. An interhemispheric, transcallosal trajectory combined with transforminal approach (n = 3); combined transforminal and subchoroidal approaches (n = 1); and, interforniceal approach (n = 1) were used. Total excision was performed in four patients. In one patient, a small part of capsule was left attached to thalamostriate vein. Symptoms of raised intracranial pressure showed improvement in all the patients with resolution of hydrocephalus. There was no tumor recurrence at follow-up. Pediatric colloid cysts are rarer than their adult counterparts due to their late detection only after manifestations of raised intracranial pressure, visual or cognitive dysfunction or drop attacks occur. Their radiological appearance varies depending upon the amount of mucoid content, cholesterol, proteins, and water content. The fast development of clinical manifestations in children may be related to rapid enlargement of cyst due to higher water content within them. The transcallosal approach is the “gold standard” of surgery and usually ensures gratifying and lasting results.

Tentorial meningiomas (TM), comprising approximately 3–6% of all intracranial meningiomas, are complex entities with an intricate relationship to surrounding structures and require multiple surgical approaches. In the present study, the rationale for deciding the approaches for TMs and the perioperative management dilemmas were evaluated. Thirty-seven patients (28 primary [supratentorial (2), infratentorial (20) and both (6)] and nine complex [cerebellopontine (CP) angle (5) and petroclival (4)] TM) underwent surgery using the occipital transtentorial, supracerebellar infratentorial, subtemporal transtentorial, bioccipital suboccipital, midline suboccipital, retrosigmoid, and combined pre and retrosigmoid approaches. The extent of excision was categorized according to Simpson’s grade. Simpson’s grade of excision was I in six, II in 11, III in nine and IV in 11 patients, respectively. Follow-up assessment (2 months to 9 years) in 27 patients (72.9%) showed that 23 patients returned to their previous activity level with either no or minimal symptoms, three returned to previous activity level with major cranial nerve palsy, and one patient required permanent assistance. One patient had recurrence and four others underwent resurgery for residual tumor. Two patients with petroclival lesions died due to aspiration pneumonitis and meningitis, respectively; one with CP angle TM presented in a poor general condition and expired following emergency ventriculoperitoneal shunt and subsequent definite surgery. Pseudomeningocele, cerebrospinal fluid leak, and cranial nerve palsy were the major morbidities. Classifying TM into medial and lateral, supra and infratentorial groups helps in deciding an appropriate and safe approach. Meticulously preserving venous sinuses is important since the risk of venous infarction cannot be predicted even with radiological good venous collaterization and apparent venous sinus blockade by tumor. Laterally situated tumors carry a better prognosis when compared to the medially situated ones. Leaving a small residual tumor in an effort to preserve important neurovascular structures does not obviate the expectation of a good long-term prognosis with minimal morbidity and low recurrence rates.

It is not always possible to differentiate infective from neoplastic brain lesions with conventional MR imaging. In this study, we assessed the utility of various perfusion indices in the differentiation of infective from neoplastic brain lesions.A total of 103 patients with infective brain lesions (group I, n=26) and neoplastic brain lesions (high-grade glioma, HGG, group II, n=52; low-grade glioma, LGG, group III, n=25) underwent dynamic contrast-enhanced MR imaging. The perfusion indices, including relative cerebral blood volume (rCBV), relative cerebral blood flow (rCBF), transfer coefficient (k(trans)) and leakage (v(e)), were calculated and their degree of correlation with immunohistologically obtained microvessel density (MVD) and vascular endothelial growth factor (VEGF) determined. The rCBV was corrected for the leakage effect. Discriminant analysis for rCBV, rCBF, k(trans) and v(e) was performed to predict the group membership of each case and post hoc analysis was performed to look for group differences.The rCBV, rCBF, k(trans), v(e), MVD and VEGF were significantly different (P0.001) between the three groups. Discriminant analysis showed that rCBV predicted 73.1% of the infective lesions, 84.6% of the HGG and 72.0% of the LGG. The rCBF classified 86.5% of the HGG, 80.0% of the LGG and 65.4% of the infective lesions. The k(trans) discriminated 98.1% of the HGG, 76.0% of the LGG and 88.5% of the infective lesions correctly. The v(e) classified 98.1% of the HGG, 76.0% of the LGG and 84.6% the infective lesions. The rCBV was correlated significantly with MVD and VEGF, while the correlation between k(trans) and MVD was not significant.Physiological perfusion indices such as k(trans) and v(e) appear to be useful in differentiating infective from neoplastic brain lesions. Adding these indices to the current imaging protocol is likely to improve tissue characterization of these focal brain mass lesions.

Lumbar disc herniation is mainly a disease of elderly people as degenerative changes progress with age. Present retrospective analysis was performed on 742 patients of lumbar disc disease operated over 11 years. Of 742 cases aged 20 years or less, 25 has been evaluated to see the clinical features, radiological features, operative findings, and outcome of lumbar disc surgery. The incidence of lumbar disc herniation in pediatric and adolescent populations was 3.5% (aged 20 years or less). All patients presented with low back pain with or without radiculopathy (n = 25). Diagnosis was easily made on magnetic resonance imaging. Gross degenerative changes in disc and end plates were uncommon (16%) in this population. The trauma may not be a predisposing factor in most of them. In 88% (n = 22) of the cases, only 1 level was affected; the commonest was L4–5 (n = 13). Disc herniation was centrolateral in 72% (n = 18) and central in 28% (n = 7). Disc was mostly soft, hydrated, and rubbery in 92% (n = 23). Disc herniation were subligamentous in 80% (n = 20) and extruded in 4% (n = 1). Sixteen percent (n = 4) of the patients had disc bulge with intact annulus. Operative intervention in the form of simple discectomy offers good result in 92% (n = 23) cases irrespective of approach and method. Longer follow-up is mandatory because the chances of recurrence or another level involvement cannot be denied.

Background. This prospective study, conducted in patients with Chiari I malformation (C I) related syringomyelia who underwent posterior decompression and duroplasty, utilizes radionuclide cisternography in order to study the cerebrospinal fluid (CSF) dynamics at the foramen magnum and to predict the clinical outcome following surgery. Methods. 17 consecutive patients of C I with syringomyelia (but without hydrocephalus or fixed atlanto-axial dislocation), underwent a detailed neurological examination and were assigned a clinical disability score based on the modified Klekamp and Samii score. A radionuclide cisternography (using Tc99m-DTPA) was performed via the lumbar route and the ascent of the tracer was followed utilizing a gamma camera immediately after injection and then sequentially after 1, 2, 4, 6 and 24 hours. After posterior decompression and duroplasty, the modified Klekamp and Samii score was repeated at follow-up visits (range: 3 months to one year) along with radionuclide cisternography at 3 months, and MR imaging at 6 months. Findings. Three patterns of tracer flow were observed: a) rapid flow (n=7); b) supratentorial subarachnoid delay (n=7); and, c) foramen magnum block (n=3). The patients having foramen magnum block had the poorest clinical scores on admission. At follow up, there was an improvement in the clinical scores so that the mean scores in all three categories reached nearly the same level. Following posterior decompression, the radionuclide cisternography performed in 10 patients showed a rapid flow of the tracer without any obstruction. The syrinx resolved in 4 of the 11 patients in whom an MRI was done. Interpretation. The patients with C I with syringomyelia may often have a free flow of tracer across the FM. Posterior decompression and duroplasty provides maximum clinical relief in patients with a demonstrable foramen magnum block on radionuclide cisternography while those with a normal flow have less relief. The symptomatology related to brain-stem compression immediately responds to the surgical procedure but the syrinx-induced signs and symptoms of spinal cord dysfunction persist.

Background. Reducible atlanto-axial dislocation (AAD) may cause severe motor and respiratory compromise due to recurrent spinal cord and/or brain stem impingement. To the best of the authors' knowledge, this is the first study concentrating on the classification, the protocol of the surgical management and the outcome of congenital, reducible AAD. Methods. 109 patients with congenital, reducible AAD underwent posterior stabilization. Their preoperative disability was graded as: I (n = 11, 10.09%) no functional disability (a history of minor trauma led to quadriparesis that subsequently improved); II (n = 31, 28.44%) independent for activities of daily living with minor disability; III (n = 42, 38.53%) partially dependent on others for their daily needs; and, IV (n = 25, 22.93%) totally dependent. They were classified into 4 groups depending upon their association with: a normal odontoid and posterior arch of atlas (n = 27); a dysplastic odontoid and normal posterior arch (n = 25); an assimilated posterior arch (n = 49); and, Arnold Chiari malformation type I (n = 8). Nine patients with a dysplastic odontoid had a hypermobile AAD with an unrestricted backward and forward movement of the axis relative to the atlas in flexion as well as in extension of the neck, respectively. The surgical procedures included Brooks' (n = 12) or modified Brooks' Cl-2 fusion (n = 39); Goel's C1-2 fusion (3); Ransford's contoured rod fusion (n = 7); Jain's occipitocervical fusion (n = 47); and, transoral decompression and Jain's occipitocervical fusion (n = 1). There were 6 peri-operative mortalities in the series. Findings. At follow-up (ranging from 3 months to 6 years; n = 86), 64 patients had shown improvement by one grade or more; 8 patients, who had a history of transient quadriparesis but were without neurological deficits at presentation, remained in grade I; 11 had achieved stabilization of neurological functions; while 3 had deteriorated despite adequate radiological reduction of AAD and fusion of the construct. A follow-up of 6 months or more was available in 79 of these 86 patients, in whom a dynamic intrathecal CT scan showed a good osseous union. Interpretation. The patients with congenital reducible AAD, depending on their surgical management, may be classified into four groups. Some patients with a dysplastic odontoid have a hypermobile AAD and require special care during intubation, positioning and stabilization. An assimilated posterior arch is often associated with asymmetrical lateral occipito-C1-C2 joint synostosis rendering transarticular screw placement difficult. The various causes of failure of constructs are discussed.

This study includes eight normal, not at-risk for deafness, neonates and infants of age ranging from 2 days to 1 year. BERA was done at 2 kHz. frequency at 80 dB intensity. In the majority of the subjects, only wave I, II, III and V could be definitely identified. It was observed that latencies of waves decreased as age of neonate/infant increased. Decrease of latency was more marked in first 6 months of life (wave V from 7.2 ms to 6. / ms) as compared to next six months (wave V from 6. 1 ms to 5.9 ms). This could be because of rapid myelination in the first six months of life.

High cervical ossified ligamentum flavum (OLF) is rare and may cause progressive quadriparesis and respiratory failure . Our two patients had unilateral OLF between C1 and C4 levels. MR showed a unilateral, triangular bony excrescence with low signal and a central, intermediate or high signal on all pulse sequences due to bone marrow within. There was Type I thecal compression (partial deficit of contrast media ring). The first patient had a linear and nodular OLF with calcification within tectorial membrane, C2-3 fusion and unilateral C2-facetal hypertrophy; and the second patient, a lateral, linear OLF with loss of lordosis and C3-6 spondylotic changes. A decompressive laminectomy using "posterior floating and enbloc resection" brought significant relief in myelopathy. Histopathology showed mature bony trabeculae, bone marrow and ligament tissue. The coexisting mobile cervical vertebral segment above and congenitally fused or spondylotic rigid segment below the level of LF may have led to abnormal strain patterns within resulting in its unilateral ossification. In dealing with cervical OLF, carefully preserving facets during laminectomy or laminoplasty helps in maintaining normal cervical spinal curvature.