Non-chordomatous clival bony tumors: A rare experience and systematic literature review.

BACKGROUND: Non-chordomatous bony tumors of the clivus are extremely rare. Site, extent, and aggressiveness of tumor limits the extent of resection. It poses challenge to the neurosurgeons due to the complexity of anatomy. There is paucity of literature exclusively on non-chordomatous bone tumors of the clivus in young adults. OBJECTIVES: To analyze the clinical presentation, imaging findings, surgical approach, complications, and outcome of primary clival bony tumors in young adults. METHODS: We retrospectively reviewed children and young adults with primary clival bony tumors excluding chordoma who underwent surgical resection between years 2010 and 2023 in our center. We analyzed the demographic details, imaging findings, operative variables, perioperative complications, length of stay, complications, and outcome at latest follow-up. RESULTS: The mean age was 17.5 ± 1.73 years (range 16 to 19 years). Headache was the presenting complaint in all four patients (100%). The mean duration of symptom was 7.25 ± 3.2 months (range 5 to 12 months). The tumor was localized in clivus in all four patients (100%). The mean length of stay in hospital was 30.5 ± 13.48 days (range 11 to 40 days). All patients underwent surgical treatment. Surgical approaches used were anterior approach in four patients (100%). Gross total excision was performed in one patient (25%), sub-total excision was performed in two patients (50%), and tumor decompression was performed in one patient (25%). Of these, three were designated as having benign tumors and one had a malignant tumor. There was no perioperative mortality. There was one mortality (25%) on 2 months follow-up due to tumor progression. Three patients (75%) had improved symptomatically at latest follow-up. Two patients (50%) received adjuvant chemoradiotherapy. The mean follow-up was 38 ± 39.29 months (range 2 to 72 months). CONCLUSION: Non-chordomatous bony tumors of the clivus are rare and often underestimated. Surgery is the treatment of choice. Tumor consistency and adhesion to critical neurovascular structures precludes gross total resection. Various approaches are in the armamentarium. Approach to be decided based on the expertise of the neurosurgeon to achieve safe maximal resection. Multidisciplinary approach is mandatory for streamlined management. Adjuvant therapy is decided based on the residual tumor following surgery.

Correction of pediatric cervical kyphosis with standalone posterior approach-a single-center experience of seven cases.

PURPOSE: To study clinical and radiological outcomes of pediatric cervical kyphosis correction with a standalone posterior cervical approach. Cervical spine kyphotic deformity in pediatric age group is a distinct entity and the management is challenging. Pediatric cervical kyphosis is less often encountered, and literature is sparse with only few case series. Management algorithms are devised keeping the flexibility of the deformity at the core of decision making. Circumferential fusion is mostly recommended for non-flexible (rigid) kyphosis. METHODS: Authors present a single center retrospective analysis of cases of pediatric cervical kyphosis managed by a standalone posterior approach. Pre- and post-operative clinical and radiological parameters were recorded and analyzed. Changes in neurological status, kyphosis correction and bony fusion were assessed. Surgical and implant related complications were noted. RESULTS: Seven cases (6 male, 1 female) were included. Mean age was 13.9±2.9 years, ranging from 8-17 years. Etiology was traumatic in 2 cases, developmental in 2, and syndromic, Hirayama disease and post-laminectomy in 1 case each. Mean kyphosis correction was 36.80±19.30 (87%±21%) with a mean pre-operative kyphosis angle of 37.80±15.30 and mean immediate post-operative kyphosis angle of 3.70±8.70. Mean hospital stay duration was 10±6 days. Median follow-up duration was 36 months. Myelopathy improved in 5 cases at last follow-up. Six cases demonstrated bony fusion at a mean follow-up of 8.4±1.5 months. CONCLUSION: Significant immediate correction in pediatric cervical kyphosis may be achieved with a standalone posterior approach with proper planning and technique in selected cases. Inserting pedicle screws at strategic locations of implant construct offer better corrections and pull-out strength and maintain long-term stability resulting in higher arthrodesis rates. Larger studies with longer follow up are needed to further ascertain the role of standalone posterior cervical approaches in pediatric cervical kyphosis.

Posterior pedicle inferior turbinate flap for recurrent cerebrospinal fluid leak following endoscopic transsphenoidal surgery.

BACKGROUND: Adequate reconstruction of skull base following endoscopic transsphenoidal surgery is the most crucial step in reducing postoperative morbidity and mortality. Although, the success rate of traditional nasoseptal flap is very high, specific surgical scenarios preclude its use. A variety of vascularised endonasal and tunnelled scalp flaps have been described in the literature to address such situations. Posterior pedicle inferior turbinate flap (PPITF) is one such locally available vascularised flap. METHODS: Two patients with recurrent CSF leak following endoscopic transsphenoidal resection of pituitary adenoma were included. The nasoseptal flap was not available in both patients due to previous surgery. Hence, a PPITF based on the posterolateral nasal artery, a branch of sphenopalatine artery, was harvested and used for skull base reconstruction. RESULTS: In both patients, CSF leak subsided in the immediate postoperative period. In one patient, sensorium improved and was subsequently discharged in stable condition. Other patient succumbed to meningitis in the postoperative period. CONCLUSIONS: The PPITF is a valuable alternative to the conventional nasoseptal flap when the latter is not available and it is very important for an endoscopic skull base surgeon to be familiar with the technique of harvesting and using the PPITF.

C19MC amplification and expression of Lin28A and Olig2 in the classification of embryonal tumors of the central nervous system: A 14-year retrospective study from a tertiary care center.

INTRODUCTION: CNS embryonal tumors (CET) other than medulloblastomas (MB) and atypical teratoid/rhabdoid tumors (AT/RTs), previously designated as 'central nervous system primitive neuroectodermal tumors' ('CNS PNETs'), are a heterogenous subset of tumors with poorly defined diagnostic criteria. Other than the subset of embryonal tumor with multilayered rosettes (ETMR) defined by C19MC amplification, most CETs are diagnosed by exclusion of other molecularly defined entities and histological mimics including MB, AT/RTs, and high-grade gliomas, and termed as CET, not otherwise specified (NOS) in the 2016 WHO classification. AIM: To reclassify 'CNS PNETs' as per WHO 2016, and estimate the true proportion of CET, NOS in a tertiary healthcare setting, and to evaluate the diagnostic utility of C19MC amplification, Lin28A and Olig2 expression in the subclassification of CETs. METHODS: Previously diagnosed cases of 'CNS PNETs' (2002-2016) were first evaluated by immunohistochemistry (IHC) for MIC2, RelaA, L1CAM, IDH1R132H, H3K27M, H3G34R, H3G34V, INI1, and BRG1 proteins and by fluorescence in-situ hybridization (FISH) for EWSR1 translocation to exclude histological mimics. The selected CETs (case cohort) and 79 histological mimics (comparison cohort) comprising of MB, AT/RT, pineal parenchymal tumors, Ewing sarcoma, esthesioneuroblastoma, intraocular medulloepithelioma, and H3G34R mutant high-grade glioma were subject to IHC for Olig2 and Lin28A, and FISH for C19MC amplification. RESULTS: Twenty-two cases of 'CNS PNETs' were retrieved, all of which were negative for the first panel of markers and showed retained INI-1/BRG1 expression. Three of them (3/22, 13.6%) showed C19MC amplification (ETMR, C19MC-altered) with ETMR histology, Lin28A positivity, and Olig2 negativity. Among the remaining 19 CETs, one showed medulloepithelioma histology (Medulloepithelioma, NOS) and remaining were non-descript small round cell tumors (CET, NOS), all negative for Lin28A. Olig2 was positive in only 3 CETs (13.6%), all being CET, NOS. All tumors in the comparison cohort were negative for C19MC amplification, Lin28A and Olig2 except for 27% of ATRTs that were Lin28A positive. CONCLUSION: ETMR, C19MC-altered constitute less than 14% of CETs, with majority remaining uncharacterized as CET, NOS. Lin28A is 100% sensitive for the detection of C19MC amplification; however, its specificity is limited by its expression in ATRTs. Olig2 expression is seen only in a small subset of CET, NOS and is of limited diagnostic utility.

Successful multimodality management of extrarenal extracranial malignant rhabdoid tumour of the left sciatic nerve mimicking a neurofibroma.

Extrarenal extracranial malignant rhabdoid tumour (MRT) is a rare and highly aggressive tumour representing <1% of paediatric soft tissue malignancies. Only a few cases of MRT of the thigh arising from the sciatic nerve have been reported in medical literature to date. A 5-year-old girl presented with progressively increasing painless lump in the posterior aspect of the left thigh. A contrast-enhanced magnetic resonance imaging (MRI) of the left thigh showed a 4.7 × 5 × 10.5 cm well-marginated, lobulated, homogeneously enhancing lesion in the posterior compartment of the left thigh along the course of the sciatic nerve. She underwent en bloc excision of the left sciatic nerve tumour and end-to-end anastomosis of the left sciatic nerve with a right sural nerve graft. Histopathological and immunohistochemical examination of the surgical specimen revealed a malignant rhabdoid tumour. INI-1 immunoexpression was lost in the tumour cells. The metastatic workup was essentially normal. Subsequently, she received post-operative radiotherapy to the tumour bed (50.4 Gray in 28 fractions over 5.5 weeks) followed by six cycles of multiagent chemotherapy with ICE (Ifosfamide, Carboplatin, and Etoposide) regimen. On the last follow-up visit, 20 months after surgery, she was in complete clinical and radiological response. Aggressive multimodality management comprising radical resection of tumour, post-operative radiotherapy to the tumour bed, and multiagent chemotherapy with ICE regimen can lead to favourable outcomes in patients with this rare tumour.

Outcome following postneurosurgical Acinetobacter meningitis: an institutional experience of 72 cases.

OBJECTIVE: The authors aimed to evaluate the antimicrobial susceptibility pattern of Acinetobacter isolates responsible for nosocomial meningitis/ventriculitis in the neurosurgical ICU. The authors also sought to identify the risk factors for mortality following Acinetobacter meningitis/ventriculitis. METHODS: This was a retrospective study of 72 patients admitted to the neurosurgical ICU between January 2014 and December 2018 with clinical and microbiological diagnosis of nosocomial postneurosurgical Acinetobacter baumanii meningitis/ventriculitis. Electronic medical data on clinical characteristics, underlying pathology, CSF cytology, antibiotic susceptibilities, and mortality were recorded. To evaluate the outcome following nosocomial postneurosurgical Acinetobacter meningitis/ventriculitis, patients were followed up until discharge or death in the hospital. Kaplan-Meier survival analysis and multivariable Cox proportional hazards models were used to compute factors affecting survival. RESULTS: The study population was divided into two groups depending on the final outcome of whether the patient died or survived. Forty-three patients (59.7%) were included in the survivor group and 29 patients (40.3%) were included in the nonsurvivor group. Total in-hospital mortality due to Acinetobacter meningitis/ventriculitis was 40.3% (29 cases), with a 14-day mortality of 15.3% and a 30-day mortality of 25%. The 43 (59.7%) patients who survived had a mean length of hospital stay of 44 ± 4 days with a median Glasgow Outcome Scale-Extended score at discharge of 6. On univariate analysis, age > 40 years (p = 0.078), admission Glasgow Coma Scale (GCS) score ≤ 8 (p = 0.003), presence of septic shock (p = 0.011), presence of external ventricular drain (EVD) (p = 0.03), CSF white blood cell (WBC) count > 200 cells/mm3 (p = 0.084), and comorbidities (diabetes, p = 0.036; hypertension, p = 0.01) were associated with poor outcome. Carbapenem resistance was not a risk factor for mortality. According to a multivariable Cox proportional hazards model, age cutoff of 40 years (p = 0.016, HR 3.21), GCS score cutoff of 8 (p = 0.006, HR 0.29), CSF WBC count > 200 cells/mm3 (p = 0.01, HR 2.76), presence of EVD (p = 0.001, HR 5.42), and comorbidities (p = 0.017, HR 2.8) were found to be significant risk factors for mortality. CONCLUSIONS: This study is the largest case series reported to date of postneurosurgical Acinetobacter meningitis/ventriculitis. In-hospital mortality due to Acinetobacter meningitis/ventriculitis was high. Age older than 40 years, GCS score less than 8, presence of EVD, raised CSF WBC count, and presence of comorbidities were risk factors for mortality.

Endoscopic controlled clipping of anterior circulation aneurysms via keyhole approach: Our initial experience.

INTRODUCTION: Surgical clipping is the most definite treatment for intracranial aneurysms. Its aim is to achieve complete aneurysmal occlusion without compromising the lumen of a parent vessel or perforators, and with minimal brain tissue trauma. OBJECTIVE: To evaluate the role of endoscopic controlled keyhole approach in clipping of anterior circulation aneurysms. MATERIALS AND METHODS: In this retrospective study, all consecutive patients undergoing endoscopic controlled clipping via the keyhole approach by the senior author during the last 1 year were included. The cases in which a microscope was used at any stage of surgery were excluded. RESULTS: Fourteen patients with anterior circulation aneurysms underwent clipping via the endoscopic keyhole approach (supraorbital and mini-pterional). Seven patients had anterior communicating (ACom) artery aneurysms, four had middle cerebral artery (MCA) bifurcation aneurysms, two had internal carotid artery bifurcation aneurysms, and one had a posterior communicating artery aneurysm. Ten patients presented with subarachnoid hemorrhage (Hunt and Hess grade I in 6 and grade II in 4 patients), whereas the remaining four were incidentally detected. The pre-clipping dissection as well as the clipping were successfully performed endoscopically in all patients. The post-clipping inspection revealed inclusion of a perforator within the clip blades in 2 patients (ACom and MCA bifurcation) that required clip readjustment. There was no residual neck/incompletely clipped aneurysm detected on post-clipping inspection. There was no morbidity directly attributable to the use of keyhole approach or the endoscope. CONCLUSION: Endoscopic keyhole approach for intracranial aneurysms combines the advantages of both keyhole approach and endoscopy. Endoscopic visualization can help to reduce chances of an incompletely clipped aneurysms/residual neck and the risk of parent vessel/perforator occlusion. However, the use of an endoscope in narrow corridors with space constraints has a learning curve that can be overcome by practicing on cadavers and initially performing several simple endoscopic procedures.

The role of neuronavigation-guided functional MRI and diffusion tensor tractography along with cortical stimulation in patients with eloquent cortex lesions.

OBJECTIVE. To effectively combine functional MRI (fMRI), diffusion tensor tractography (both guided by neuronavigation) along with cortical stimulation (CS) for surgery of eloquent cortex (EC) lesions. MATERIALS AND METHOds. Fifteen patients with lesions adjacent to the eloquent motor and sensory cortex were included. Preoperative fMRI and diffusion tensor imaging were performed and then integrated into the neuronavigation system. Intraoperative CS of sensory/motor cortex was performed to localize the EC under awake condition and this was correlated with areas active on fMRI utilizing neuronavigation. For excision of the deeper structures, CS, and tractography guided by neuronavigation were utilized. RESULTS. A total of 127 cortical sites were evaluated with CS in 15 patients. The overall sensitivity, specificity, and accuracy of fMRI were 79%, 85%, and 82%, respectively, keeping the areas positive on CS as a referential parameter. Tractography helped in resecting the deeper areas of the tumor, but was not very accurate due to brain shift. However, it was useful in roughly assessing the deeper areas close to the long tracts. The risk of developing persistent neurological deficits was 6%. Pathologies included gliomas in ten patients, cavernous malformation in two patients, meningioma in one patient, and focal cortical dysplasia and Dysembryonic neuroepithelial tumor in one patient each. Near total excision was achieved in 7/10 (> 95% excision) gliomas and a total excision in all others lesions. CONCLUSIONS. Lesions directly over the EC present a special surgical challenge. The challenge lies in excising these lesions without producing any deficits. These goals may be achieved better by combined use of multimodal neuronavigation (fMRI and tractography) and intraoperative mapping with CS under awake conditions.

Unilateral Autosomal Recessive Anophthalmia in a Patient with Cystic Craniopharyngioma.

Anophthalmia is a rare ocular malformation. It is a genetically determined disorder and is typically associated with syndromes. However, sporadic nonsyndromic familial as well as non-familial cases of anophthalmia have also been reported. Non-syndromic familial cases are usually bilateral and have been attributed to autosomal recessive, autosomal dominant, and X-linked inheritance patterns. The authors hereby report a rare case of autosomal recessive unilateral anophthalmia in a patient with no other associated congenital anomaly. Patient was operated for craniopharyngioma. The clinical, radiological and intraoperative findings are discussed.

Severe valproate induced hyperammonemic encephalopathy successfully managed with peritoneal dialysis.

Valproic acid (VPA) is a commonly used drug for epilepsy, psychiatric disorders and migraine and is frequently used in neurosurgical intensive care units. Though most of its side-effects are mild and transient, certain idiosyncratic side-effects have been attributed to VPA. Valproate induced hyperammonemia (VIH) is one such side-effect. VIH can produce symptoms of encephalopathy known as valproate induced hyperammonemic encephalopathy (VHE). VIH and VHE usually respond to withdrawal of VPA. However, in some cases VHE can be unresponsive to supportive measures and severe enough to be life-threatening. In such cases, dialysis can be used to rapidly reverse hyperammonemia and VHE and can prove to be a lifesaving measure. We report such a case of VIH and life-threatening VHE in a postoperative neurosurgical patient that was managed successfully with peritoneal dialysis.

The Displacement Patterns of Petrous Internal Carotid Artery and Its Morphometric Relations with Vidian Canal in Petroclival Chondrosarcomas Relevant to Extended Endoscopic Endonasal Approaches: A Radiological Study.

BACKGROUND: Extended endoscopic endonasal approaches (EEAs) to petroclival chondrosarcomas (PCs) require a thorough understanding of skullbase anatomy, especially the anatomy of petrous internal carotid artery (pICA), as ICA injury is the most dreaded complication of extended EEAs. We conducted this study to determine the displacement patterns of pICA in patients with PCs. METHODS: Contrast enhanced computed tomography scan and angiography images of patients with PCs were analyzed for following parameters-antero-posterior, cranio-caudal, medio-lateral, and direct distances between anterior genu of petrous internal carotid artery (AGpICA) and posterior end of Vidian canal (pVC). pICA encasement/narrowing by tumor was noted on magnetic resonance imaging. RESULTS: We studied 11 patients with histopathologically proven PCs. pICA encasement/narrowing and pVC destruction were observed in one patient each. The mean antero-posterior and cranio-caudal distances on tumor side/normal side were 7.7 ± 1.9/6.4 ± 1.0 mm & 4.5 ± 1.5/3.4 ± 0.9 mm, respectively. The overall displacement was posterior & superior. Medio-lateral displacement was seen in 4 patients (lateral in 3 and medial in 1). In rest, AGpICA was centered on pVC. The mean direct distance was 9.4 ± 2.5 mm. In 3 patients with displacement seen in all three axes, direct distance was measured by the "cuboid method." Overall, posterior-superior-lateral, posterior-superior, and anterior-inferior were the common displacement patterns of AGpICA relative to pVC. CONCLUSIONS: The displacement patterns of AGpICA in PCs are variable. An individualized approach with meticulous analysis of preoperative imaging can help in determining the relation between AGpICA and pVC. This detailed morphometric information can facilitate better orientation to altered anatomy, which can be helpful in preventing pICA injury during extended EEAs.

A computed tomography (CT)-based morphometric study of various skull base parameters and their anatomical relationships relevant to endoscopic endonasal skull base surgery.

Background: Endoscopic skull base surgery requires a thorough understanding of skull base anatomy. Orientation to regional anatomy to avoid complications like internal carotid artery injury can be assisted by knowledge of certain bony landmarks. These landmarks are themselves highly variable structures. This study focuses on the radiological morphometric characterization of these landmarks, which can be of great assistance to surgeons for better planning of endoscopic skull base approaches. Methods: Computed tomography scans of patients without skull base pathologies were analyzed retrospectively for the following parameters - Vidian canal (VC) length, VC and foramen rotundum (FR) distance from midline, the angle between the axis of VC and petrous internal carotid artery (pICA) and between VC and palatovaginal canal, the horizontal, vertical and direct distances between VC and FR and the patterns of sphenoid sinus (SS) pneumatization. Results: The VC-pICA angle was more obtuse and VC and FR were placed farther off the midline on the left as compared to the right side. Similarly, the distances between VC and FR were more on the left side. The VC length and distance of VC and FR from the midline were longer in males than in females. The VC-pICA angle was more obtuse in females. The post-sellar variant was the predominant pneumatization pattern seen (57.9%), and the incidence of lateral recess pneumatization was 15%. Conclusion: The results of our study can be utilized for a better understanding of the anatomy of the skull base. In skull base pathologies with distorted anatomical landmarks, a basic understanding of their interrelations can be used to have a better anatomical orientation. All these measures can help in avoiding complications and make extended endoscopic approaches safe.

Papillary Tumors of Pineal Region: A Single-Center Experience in Management of 11 Cases.

BACKGROUND: Papillary tumors of pineal region (PTPR) comprise a very rare subset of pineal region tumors that have been recently described. Literature on the management and outcome of PTPR is scarce owing to the rarity of these tumors. To address this lacuna, we analyzed our experience in management of PTPR. METHODS: We retrospectively analyzed the outcome of 11 patients with histopathologically proven PTPR who underwent surgical excision at our center. RESULTS: Mean patient age was 33.3 years (range, 12-45 years), and male-to-female ratio was 1.75:1. Headache was the most common presentation followed by visual disturbances, altered sensorium, Perinaud syndrome, and seizures. Cerebrospinal fluid diversion was required in 6 patients. Krause approach was the most common approach used for tumor excision (9/11 cases). There was no perioperative mortality. Two patients were lost to follow-up. In the remaining 9 patients, the average follow-up period was 45 months (range, 12-79 months). On first postoperative magnetic resonance imaging, 8 patients showed no evidence of residual tumor (gross total resection), while 1 patient had small residual tumor (near-total resection) that remained stable during follow-up. Four patients underwent adjuvant chemoradiotherapy. None of the patients developed recurrence during follow-up. CONCLUSIONS: PTPR are a rare subgroup of pineal region tumors with distinct cells of origin but presentation similar to other pineal region tumors. Surgical resection constitutes the mainstay of management, and the extent of resection appears to be the most important determinant of prognosis. The role of adjuvant therapy still needs to be determined.

Bifrontal basal interhemispheric approach for midline suprasellar tumors: our experience with forty-eight patients.

INTRODUCTION: Suprasellar lesions present a surgical challenge due to their complex relationship with surrounding neurovascular structures. Of the approaches for these lesions, bifrontal basal interhemispheric approach (BBIA) gives a midline perspective of suprasellar anatomy and has certain advantages over lateral approaches. MATERIALS AND METHODS: We retrospectively reviewed 48 patients with suprasellar lesions operated over 7 years via BBIA. Patient records, operation notes, radiology, and outpatient files were scrutinized to collect data. RESULTS: During the study period 48 patients (mean age 33 years, M:F 1.5:1) were operated by this approach. The clinical features included: Visual field deficits in 33 (69%) patients, with 6 of them being blind, diabetes insipidus in 7, growth retardation in 5, and subarachnoid hemorrhage in three patients. Cranopharyngiomas (52%) and meningiomas (16.7%) were the most common pathologies. Dyselectrolytemia (18, 40%) and diabetes insipidus (15, 33%) were the most common complications. Postoperative seizures, meningitis, subdural effusion, and retraction site contusion were seen in 12 (27%), 5 (11%), 4 (9%), and 1 (2.2%) patient, respectively. Three patients died postoperatively and 19 (40%) patients required hormone replacement therapy. Amongst the patients with preoperative visual deficits, 23 (70%) had improvement in visual functions, in six (20%), there was no change and four (8.3%) patients had visual deterioration. CONCLUSION: BBIA provides a true midline perspective and orientation, and permits complete and safe removal of midline suprasellar lesions in majority of cases. This approach is especially useful in retrochiasmatic tumors and in residual/recurrent tumors providing virgin plane of dissection.

Tadpole Sign in Filum Terminale Paragangliomas.

Two normotensive male patients came with complaints of low back pain. Contrast-enhanced magnetic resonance imaging of the lumbosacral spine revealed an enhancing intradural extramedullary lesion (at the L4-L5 vertebral level in the first patient and at the L2-L3 vertebral level in the second patient). The tumor resembled the head and caudal blood vessels the tail of a tadpole, thereby giving the "tadpole sign." This sign is an important radiologic and histopathologic correlate, which is helpful in preoperative diagnosis of spinal paraganglioma.

Comparison of Infection Rates Following Immediate and Delayed Cranioplasty for Postcraniotomy Surgical Site Infections: Results of a Meta-Analysis.

Postoperative surgical site infections (SSIs) in neurosurgery are rare. However, they pose a formidable challenge to the treating neurosurgeon and substantially worsen patient outcomes. These infections require prompt intervention in the form of débridement, including removal of craniotomy bone. Reconstruction of the craniotomy defect can be performed along with the débridement or can be performed at a later time. Although there have been concerns about performing cranioplasty at the same time as débridement, recent studies have advocated performance of cranioplasty at the same time as the débridement, as it avoids the morbidity associated with having a craniectomy defect and avoids the need for another surgical procedure. We conducted a literature review and meta-analysis to examine the data on immediate cranioplasties and delayed cranioplasties performed for postcraniotomy SSIs. We analyzed 15 articles with a total of 353 patients. Our analysis revealed that the pooled proportion of treatment failure was 10.4% (95% confidence interval [CI] 5.9%-17.8%) when an immediate cranioplasty was done and 16.1% (95% CI 7.2%-32.1%) when delayed cranioplasty was done. The pooled proportion of treatment failure was 12% (95% CI 5.9%-22.9%) when the same bone was used for cranioplasty and was 8% (95% CI 3%-20%) when prosthetic material such as titanium was used for cranial vault reconstruction. Thus, the rate of treatment failure was less when an immediate single-stage cranioplasty was done compared with a delayed cranioplasty following SSIs.

An assessment of the variation in the practice of lumbar discectomy and its role in axial back pain.

Background: Lumbar discectomy is performed for symptomatic lumbar disc herniation and is one of the most widely performed spinal surgical procedures worldwide in a variety of ways. This survey aimed at providing an overview/perspective of different practice patterns and the impact of lumbar discectomy on axial back pain with or without sciatica. Methods: An online survey was performed using the application "Google Forms." The link to the questionnaire was distributed to neurosurgeons through personal E-mail and social media platforms. Results: We received 333 responses. The largest percentage of responses across five continents was from Asia (66.97%, n = 223). The mean age of the respondents was 40.08 ± 10.5 years. A total of 66 respondents (20%) had a spine practice of 7%-90%, and 28 respondents had a spine practice of 90%-100% (8.4%). The number of respondents who practiced microscopic discectomy using a tubular retractor (n = 143 respondents, 42.9%) was nearly equal to the number of respondents who practiced open discectomy (n = 142 respondents, 42.6%). An almost equal proportion of respondents believed discectomy does not help in relieving axial back pain. Only 20.4% (n = 68) of respondents recommend bed rest for a longer duration postoperatively. Conclusions: Our survey revealed that only 22.2% of spine surgeons recommended discectomy in patients with radiological disc herniation with axial back pain alone and preferred a minimally invasive method of discectomy. Almost half of them believed discectomy to be ineffective for axial low back pain and only a few recommended prolonged bed rest postoperatively.

Suprameatal Extension of Retrosigmoid Approach in Microvascular Decompression for Trigeminal Neuralgia with Petrous Endostosis: Case Report and Literature Review.

Petrous endostosis or prominent suprameatal tubercle is a rare entity which may prevent adequate microscopic exposure of the trigeminal nerve root entry zone during microvascular decompression (MVD) for trigeminal neuralgia. We present a rare case of trigeminal neuralgia (TN) with petrous endostosis, which was managed adequately by partial removal of the prominent suprameatal tubercle to improve the obscured site of neurovascular conflict and enabled complete MVD. Through this manuscript, we additionally discuss the nuances involved in this extension of the standard retrosigmoid approach in light of the published literature. Petrous endostosis encountered during MVD for TN can impose an operative challenge. Suprameatal extension of the standard retrosigmoid approach improves exposure at the site of neurovascular conflict but requires utmost care and attention to avoid complications. We emphasize recognizing this anatomical variation in the preoperative period to predict an operative difficulty, ensure appropriate patient counselling, and avoiding surgical complications.

Use of Intraoperative Imaging to Preserve C1-C2 Mobility in Complex Atlas-Hangman Fractures.

Background: Combination fractures of the C1-C2 complex especially atlas and hangman are relatively uncommon and management usually compromises C1-C2 mobility. Objective: To evaluate the treatment of combined C1- hangman's fracture with and without intraoperative O- arm based navigation system, and its outcome in terms of preserving C1-C2 mobility. Methods: This was a case series of patients with combined C1 and hangman's fracture, managed at a tertiary care hospital during February 2009 to December 2016. Neurological function assessed with American Spine Injury Association (ASIA) impairment scale. Radiological fusion of the operated segment assessed with computed tomographic scan, criteria used for successful fusion included formation of callus across the fracture. Preservation of rotational motion between C1 and C2 was assessed by cervical flexion rotation (CFR) test. Results: We included 10 patients (male/female: 9/1; mean 47.7 ± 17.5 years) in our study. Operative intervention was performed in 9 patients. We used intraoperative computed tomogram (CT) scan with navigation in 5 patients. The mean follow-up period was 28.7 months (range 6 to 70 months). Neurological recovery occurred in all 4 patients with preoperative neurological deficits. Radiological fusion occurred in all cases. Rotation at C1-2 was preserved in all 5 cases operated under O-arm guidance and in one patient with type 1 fracture who was managed conservatively. Conclusions: The goals in treating these complex fractures are to achieve early maximum stability and preserving maximum range of motion. These are often competing phenomena, which can be achieved by using intra operative CT scan and navigation system.

Single-Stage Posterior Only Approach for Unilateral Atlantoaxial Spondyloptosis with type-II odontoid Fracture in Pediatric Patients.

Objective: When there is a complete slippage of facet joints of C1 over C2 such that there is no contact between the articulating surfaces of C1 and C2, the condition is known as atlantoaxial spondyloptosis (AAS). AAS represents an extremely rare manifestation of atlantoaxial instability. This study was performed to highlight the presentation, radiological features, and management of unilateral AAS in pediatric patients. Material and Methods: We retrospectively identified four pediatric patients with AAS from our hospital records in the last 6 years (2014-2019). Results: Among the four patients with unilateral AAS, three were posttraumic and one was diagnosed with craniovertebral junction tuberculosis (CVJ TB). All the patients had a varying degree of spastic quadriparesis on presentation. One patient with CVJ TB presented with neck tilt. All patients with traumatic unilateral AAS were associated with an odontoid fracture. These patients underwent C1-C2 fixation with complete reduction of spondyloptosis using the techniques of joint manipulation and joint remodeling with a posterior only approach. Complete reduction of AAS in patients with trauma was also associated with the realignment of the odontoid fracture. All patients improved neurologically after surgery and achieved excellent correction of the deformity on a follow-up imaging. Conclusion: Pediatric unilateral AAS is an extremely rare phenomenon. A single-stage posterior approach with C1-C2 fixation is a feasible technique for the treatment of this seemingly difficult to correct deformity in pediatric patients and the clinical outcomes are excellent.