Outcome of Surgery for Congenital Craniovertebral Junction Anomalies with Atlantoaxial Dislocation/Basilar Invagination: A Retrospective Study of 94 Patients

OBJECTIVE

To evaluate the results of surgery for congenital craniovertebral junction (CVJ) anomalies with atlantoaxial dislocation (AAD)/basilar invagination (BI) and compare the results of transoral odontoidectomy and posterior fusion (TOO+PF) with only posterior fusion (PF) in patients with irreducible AAD/BI.

METHODS AND RESULTS

All 94 patients with congenital CVJ anomalies with AAD/BI operated on during the 3-year study period (June 2013-May 2016) were included. Of these patients, 55 had irreducible AAD/BI and the remaining 39 had reducible AAD/BI. TOO+PF was restricted to patients (34/94; 36.2%) with irreducible AAD/BI when reduction and realignment by intraoperative C1-C2 facet joint manipulation were considered technically difficult and risky. The remaining patients with irreducible AAD/BI and all the patients with reducible AAD/BI (60/94; 63.8%) were managed with only posterior fusion. Poor preoperative Nurick grade, preoperative dyspnea/lower cranial nerve deficits, and syringomyelia were associated with significantly higher incidence of postoperative pulmonary complications. Follow-up ≥3 months (final follow-up) was available for 87 patients. Good outcome (Nurick grade 0-3) at final follow-up was noted in 90% (45/50) of the patients with irreducible AAD/BI and 91.9% (34/37) of the patients with reducible AAD/BI. Preoperative poor Nurick grade (4-5) was the only factor associated with poor outcome. No significant difference in perioperative complications, outcome, and fusion was noted between patients who underwent TOO+PF or only PF for irreducible AAD/BI.

CONCLUSIONS

Many of the patients with congenital AAD/BI showed remarkable recovery after surgery. Preoperative poor Nurick grade (4-5) is associated with poor outcome. TOO+PF is a safe alternative treatment option for irreducible AAD/BI when only PF techniques are technically difficult/risky.

Microsurgery for Spetzler-Martin Grade I-III Arteriovenous Malformations: Analysis of Surgical Results and Correlation of Lawton-Young Supplementary Grade and Supplemented Spetzler-Martin Score with Functional Outcome

OBJECTIVE

To analyze the results of microsurgery for Spetzler-Martin (SM) grade I-III AVMs and evaluate the correlation of the Lawton-Young (LY) supplementary grade, supplemented Spetzler-Martin (SM-Supp/combined) score with the functional outcome.

METHODS

A total of 42 patients with SM grade I-III AVMs who had undergone surgery at our institute during a 3-year period (June 2013 to May 2016) were included in the present study.

RESULTS

All 42 patients had undergone primary surgery without previous embolization. Three patients (7.1%) had died due to surgical site hematoma in the postoperative period. One patient was lost to follow-up. The mean follow-up period for the remaining patients was 27 ± 14 months (range, 12-62 months). At the final follow-up examination of ≥12 months (FFU), 92.7% of the patients had a good outcome (modified Rankin scale [mRS] score ≤1), with an improved or unchanged mRS score in 87.8%. An AVM size >3 cm, diffuse AVM, SM grade III, and SM-Supp score >5 were associated with worsened mRS score at discharge and FFU. Higher LY grade (IV and V), eloquent AVM location, deep venous drainage, age >40 years, and unruptured presentation were not associated with worsened mRS score at both discharge and FFU. Of the 20 ARUBA-eligible patients, 19 (95%) had good outcomes. Postoperative angiograms for 39 patients revealed complete excision of the AVM in 37 (94.9%) and a residual AVM in 2 (5.1%).

CONCLUSIONS

High cure rates and excellent clinical outcomes can be expected with microsurgery for most patients with SM grade I-III AVMs. An AVM size >3 cm, diffuse AVM nidus, SM grade III, and SM-Supp score >5 are associated with postoperative worsening of functional scores in patients with SM grade I-III AVMs.

Far lateral approach without occipital condylar resection for intradural ventral/ventrolateral foramen magnum tumors and aneurysms of V4 segment of vertebral artery: Review of surgical results

BACKGROUND

Controversies exist regarding the need and extent of condylar resection for safe surgical management of intradural ventral/ventrolateral foramen magnum (VFM) tumors and aneurysms of V4 segment of vertebral artery (VA) by far lateral approach. This retrospective study was conducted to evaluate the results of basic far lateral approach(retrocondylar approach) without upfront occipital condylar resection.

METHODS AND RESULTS

Twenty one patients underwent surgery via far lateral approach for intradural VFM tumors and aneurysms of V4 segment of VA at Sri Sathya Sai Institute of Higher Medical Sciences during 9 years(2008-2016) study period. Eight patients had VA aneurysms and 13 patients had intradural VFM tumors. After basic far lateral approach(retrocondylar approach), dura was opened and checked if the exposure was adequate for safe surgery. Retrocondylar approach provided adequate exposure for all these lesions and resection of occipital condyle/jugular tubercle was not required in any of these cases. Skeletonization or transposition of VA was not done in any of these cases. Gross total resection of the tumor could be done in 9 patients(9/13-69.2 %) and near total excision (>95 %) in 4 patients (4/13-30.8 %). Seven of the 8 VA aneurysms were successfully clipped. Outcome at a final follow up of 3 months or more was good(mRS<2) in 19 patients(19/21-90.5 %) and poor in 2 patients. Complications included lower cranial nerve deficits [transient-2/21(9.5 %), persisting-2/21(9.5 %)], motor deficits(2/21-9.5%), seventh nerve paresis(1/21-4.8%), sixth nerve paresis(2/21-9.5%) and pseudomeningocele(1/21-4.8%).

CONCLUSION

Basic far lateral (retrocondylar) approach provides excellent exposure for majority of VFM tumors and aneurysms of V4 segment of VA. Condylar resection(transcondylar approach), drilling of jugular tubercle (transtubercular approach), skeletonization/transposition of VA might not be required for safe surgical management of majority of these lesions.

Microsurgical Clipping of Distal Basilar Trunk Aneurysm during Adenosine-Induced Profound Hypotension

A 46-year-old male presented with a history of sudden severe headache 1 week back, altered sensorium and right hemiparesis for 2 days. On examination, Glasgow Coma Scale (GCS) was E4V4M6 and the patient had right hemiparesis (power – 4/5). Computed tomography (CT) revealed diffuse subarachnoid hemorrhage (Fisher's Grade III). CT angiogram revealed distal basilar trunk aneurysm arising between the origin of the left posterior cerebral artery and superior cerebellar artery, ectatic dilatation of distal basilar trunk, and a left middle cerebral artery (MCA) bifurcation aneurysm. Basilar trunk aneurysm was approached through subtemporal route and aneurysm was clipped during adenosine-induced profound hypotension (AIPH) without application of temporary clip. Single bolus 6 mg of adenosine was given, and aneurysm was successfully clipped during AIPH (systolic <60 mmHg). There were no complications related to adenosine. Ectatic part of distal basilar trunk was wrapped with Teflon. The left MCA bifurcation aneurysm was clipped in the same session. At 3-month follow-up, the patient's sensorium was normal (GCS-E4V5M6) and the right hemiparesis improved (4+/5). Adenosine enhances the safety of clipping these aneurysms by providing transient cardiac arrest or profound hypotension. In developing countries, microsurgical clipping is a cost-effective treatment option for basilar artery aneurysms.

A points-based algorithm for prognosticating clinical outcome of Chiari malformation Type I with syringomyelia: results from a predictive model analysis of 82 surgically managed adult patients

OBJECTIVE Although various predictors of postoperative outcome have been previously identified in patients with Chiari malformation Type I (CMI) with syringomyelia, there is no known algorithm for predicting a multifactorial outcome measure in this widely studied disorder. Using one of the largest preoperative variable arrays used so far in CMI research, the authors attempted to generate a formula for predicting postoperative outcome. METHODS Data from the clinical records of 82 symptomatic adult patients with CMI and altered hindbrain CSF flow who were managed with foramen magnum decompression, C-1 laminectomy, and duraplasty over an 8-year period were collected and analyzed. Various preoperative clinical and radiological variables in the 57 patients who formed the study cohort were assessed in a bivariate analysis to determine their ability to predict clinical outcome (as measured on the Chicago Chiari Outcome Scale [CCOS]) and the resolution of syrinx at the last follow-up. The variables that were significant in the bivariate analysis were further analyzed in a multiple linear regression analysis. Different regression models were tested, and the model with the best prediction of CCOS was identified and internally validated in a subcohort of 25 patients. RESULTS There was no correlation between CCOS score and syrinx resolution (p = 0.24) at a mean ± SD follow-up of 40.29 ± 10.36 months. Multiple linear regression analysis revealed that the presence of gait instability, obex position, and the M-line-fourth ventricle vertex (FVV) distance correlated with CCOS score, while the presence of motor deficits was associated with poor syrinx resolution (p ≤ 0.05). The algorithm generated from the regression model demonstrated good diagnostic accuracy (area under curve 0.81), with a score of more than 128 points demonstrating 100% specificity for clinical improvement (CCOS score of 11 or greater). The model had excellent reliability (κ = 0.85) and was validated with fair accuracy in the validation cohort (area under the curve 0.75). CONCLUSIONS The presence of gait imbalance and motor deficits independently predict worse clinical and radiological outcomes, respectively, after decompressive surgery for CMI with altered hindbrain CSF flow. Caudal displacement of the obex and a shorter M-line-FVV distance correlated with good CCOS scores, indicating that patients with a greater degree of hindbrain pathology respond better to surgery. The proposed points-based algorithm has good predictive value for postoperative multifactorial outcome in these patients.

Analogous Three-Dimensional Constructive Interference in Steady State Sequences Enhance the Utility of Three-Dimensional Time of Flight Magnetic Resonance Angiography in Delineating Lenticulostriate Arteries in Insular Gliomas: Evidence from a Prospective Clinicoradiologic Analysis of 48 Patients

BACKGROUND

Three-dimensional (3D) time of flight (TOF) imaging is the current gold standard for noninvasive, preoperative localization of lenticulostriate arteries (LSAs) in insular gliomas; however, the utility of this modality depends on tumor intensity.

METHODS

Over a 3-year period, 48 consecutive patients with insular gliomas were prospectively evaluated. Location of LSAs and their relationship with the tumor were determined using a combination of contrast-enhanced coronal 3D TOF magnetic resonance angiography and coronal 3D constructive interference in steady state (CISS) sequences. These findings were analyzed with respect to extent of tumor resection and early postoperative motor outcome.

RESULTS

Tumor was clearly visualized in 29 (60.4%) patients with T1-hypointense tumors using 3D TOF and in all patients using CISS sequences. Using combined 3D TOF and CISS, LSA-tumor interface was well seen in 47 patients, including all patients with T1-heterointense or T1-isointense tumors. Extent of resection was higher in the LSA-pushed group compared with the LSA-encased group. In the LSA-encased group, 6 (12.5%) patients developed postoperative hemiparesis; 2 (4.2%) cases were attributed to LSA injury.

CONCLUSIONS

Contrast-enhanced 3D TOF can delineate LSAs in almost all insular gliomas but is limited in identifying the LSA-tumor interface. This limitation can be overcome by addition of analogous CISS sequences that delineate the LSA-tumor interface regardless of tumor intensity. Combined 3D TOF and 3D CISS is a useful tool for surgical planning and safer resections of insular tumors and may have added surgical relevance when included as an intraoperative adjunct.

Does the mesodermal derangement in Chiari Type I malformation extend to the cervical spine? Evidence from an analytical morphometric study on cervical paraspinal muscles

OBJECTIVE

The mesodermal derangement in Chiari Type I malformation (CMI) has been postulated to encompass the cervical spine. The objectives of this study were to assess the cross-sectional areas (CSAs) of cervical paraspinal muscles (PSMs) in patients with CMI without syringomyelia, compare them with those in non-CMI subjects, and evaluate their correlations with various factors.

METHODS

In this retrospective study, the CSAs of cervical PSMs in 25 patients were calculated on T2-weighted axial MR images and computed as ratios with respect to the corresponding vertebral body areas. These values and the cervical taper ratios were then compared with those of age- and sex-matched non-CMI subjects and analyzed with respect to demographic data and clinicoradiological factors.

RESULTS

Compared with the non-CMI group, the mean CSA values for the rectus capitis minor and all of the subaxial PSMs were lower in the study group, and those of the deep extensors were significantly lower (p = 0.004). The cervical taper ratio was found to be significantly higher in the study cohort (p = 0.0003). A longer duration of symptoms and a steeper cervical taper ratio were independently associated with lower CSA values for the deep extensors (p = 0.04 and p = 0.03, respectively). The presence of neck pain was associated with a lower CSA value for the deep flexors (p = 0.03).

CONCLUSIONS

Patients with CMI demonstrate alterations in their cervical paraspinal musculature even in the absence of coexistent syringomyelia. Their deep extensor muscles undergo significant atrophic changes that worsen with the duration of their symptoms. This could be related to a significantly steeper cervical taper ratio that their cervical cords are exposed to. Neck pain in these patients is related to atrophy of their deep flexor muscles. A steeper cervical taper ratio and alterations in the PSMs could be additional indicators for surgery in patients with CMI without syringomyelia.

Giant multi-compartmental suprasellar Rathke's cleft cyst with restriction on diffusion weighted images

Rathke's cleft cysts are congenital lesions seen in sellar-suprasellar regions. We report a case of giant Rathke cyst in a 43-year-old patient with multi-compartmental involvement who presented with seizures with almost normal visual acuity. We discuss radiological and pathological features of various differential diagnoses for the giant suprasellar Rathke's cyst.

Lumbar paraspinal muscle morphometry and its correlations with demographic and radiological factors in adult isthmic spondylolisthesis: a retrospective review of 120 surgically managed cases

OBJECTIVE The objective of this study was to assess the cross-sectional areas (CSAs) of lumbar paraspinal muscles in adults with isthmic spondylolisthesis (IS), to compare them with those in the normative population, and to evaluate their correlations with demographic factors and MRI changes in various spinal elements. METHODS The authors conducted a retrospective study of patients who had undergone posterior lumbar interbody fusion for IS, and 2 of the authors acting as independent observers calculated the CSAs of various lumbar paraspinal muscles (psoas, erector spinae [ES], multifidus [MF]) on preoperative axial T2-weighted MR images from the L-3 to L-5 vertebral levels and computed the CSAs as ratios with respect to the corresponding vertebral body areas. These values were then compared with those in an age- and sex-matched normative population and were analyzed with respect to age, sex, duration of symptoms, grade of listhesis, and various MRI changes at the level of the listhesis (pedicle signal change, disc degeneration, and facetal arthropathy). RESULTS Compared with values in normative controls, the mean CSA value for the ES muscle was significantly higher in the study cohort of 120 patients (p = 0.002), whereas that for the MF muscle was significantly lower (p = 0.009), and more so in the patients with PSC (p = 0.002). Magnetic resonance imaging signal change in the pedicle was seen in half of the patients, all of whom demonstrated a Type 2 change. Of the variables tested in a multivariate analysis, age independently predicted lower area values for all 3 muscles (p ≤ 0.001), whereas female sex predicted a lower mean psoas area value (p < 0.001). None of the other variables significantly predicted any of the muscle area values. A decrease in the mean MF muscle area value alone was associated with a significantly increased likelihood of a PSC (p = 0.039). CONCLUSIONS Compared with normative controls, patients with IS suffer selective atrophy of their MF muscle, whereas their ES muscle undergoes a compensatory hypertrophy. Advancing age has a detrimental effect on the areas of the lumbar PSMs, whereas female sex predisposes to a decreased psoas muscle area. Multifidus muscle atrophy correlates with PSC, indicating the role of this deep stabilizer in the biomechanical stability of spondylolisthetic spines. This may be of clinical significance in targeted physiotherapy programs during the conservative management of IS.

A value-based, no-cost-to-patient health model in the developing world: Critical appraisal of a unique patient-centric neurosurgery unit

Background:

It is well-accepted that the current healthcare scenario worldwide is due for a radical change, given that it is fraught with mounting costs and varying quality. Various modifications in health policies have been instituted toward this end. An alternative model, the low-cost, value-based health model, focuses on maximizing value for patients by moving away from a physician-centered, supply-driven system to a patient-centered system.

Methods:

The authors discuss the successful inception, functioning, sustainability, and replicability of a novel health model in neurosurgery built and sustained by inspired humanitarianism and that provides all treatment at no cost to the patients irrespective of their socioeconomic strata, color or creed.

Results:

The Sri Sathya Sai Institute of Higher Medical Sciences (SSSIHMS) at Whitefield, Bengaluru, India, a private charitable hospital established in 2001, functions on the ideals of providing free state-of-the-art healthcare to all in a compassionate and holistic manner. With modern equipment and respectable outcome benchmarks, its neurosurgery unit has operated on around 18,000 patients since its inception, and as such, has contributed INR 5310 million (USD 88.5 million) to society from an economic standpoint.

Conclusions:

The inception and sustainability of the SSSIHMS model are based on self-perpetuating philanthropy, a cost-conscious culture and the dissemination of human values. Replicated worldwide, at least in the developing nations, this unique healthcare model may well change the face of healthcare economics.

Double-clip technique for the microneurosurgical management of very small (< 3 mm) intracranial aneurysms

BACKGROUND

The treatment of very small (≤ 3 mm) aneurysms is technically challenging. Mini-clips used for clipping these small aneurysms have a smaller closing force compared with standard clips.

OBJECTIVE

To describe the double-clip technique for very small aneurysms.

METHODS

The double-clip technique, a parallel duplication clipping technique of booster clipping, is used by the senior author for clipping very small aneurysms with morphology suitable for the application of 2 clips. The aneurysm is clipped after application of temporary clip(s), administration of adenosine, or both. An initial mini-clip is applied, leaving a small residual neck sufficient for application of the second mini-clip. A second mini-clip of the same size and shape is applied on the residual neck parallel to the initial clip. The initially applied mini-clip, which is in close contact with the second clip, supports the second clip and prevents its slippage. This technique was retrospectively reviewed over a 13-year period (1997-2009). There were 3246 patients with 4757 aneurysms treated in the same period.

RESULTS

The outcomes of 39 patients with 40 very small aneurysms clipped with the double-clip technique were analyzed. None of the patients had technique-related complications. Postoperative angiograms revealed complete aneurysm occlusion of 39 aneurysms and a small residual neck in 1 aneurysm. No parent artery obstruction was observed in the postoperative angiogram.

CONCLUSION

The double-clip technique is a safe and effective variation of booster clipping in the treatment of very small aneurysms with suitable morphology.

Paraspinal muscle morphometry in cervical spondylotic myelopathy and its implications in clinicoradiological outcomes following central corpectomy

Object

The objective of this study was to assess the cross-sectional areas (CSAs) of the superficial, deep flexor (DF), and deep extensor (DE) paraspinal muscles in patients with cervical spondylotic myelopathy (CSM), and to evaluate their correlations with functional status and sagittal spinal alignment changes following central corpectomy with fusion and plating.

Methods

In this retrospective study of 67 patients who underwent central corpectomy with fusion and plating for CSM, the CSAs of the paraspinal muscles were calculated on the preoperative T2-weighted axial MR images and computed as ratios with respect to the corresponding vertebral body areas (VBAs) and as flexor/extensor CSA ratios. These ratios were then compared with those in the normative population and analyzed with respect to various clinicoradiological factors, including pain status, Nurick grade, and segmental angle change at follow-up (SACF).

Results

The mean CSA values for all muscle groups and the DF/DE ratio were significantly lower in the study cohort compared with an age- and sex-matched normative study group (p < 0.001). Among various independent variables tested in a multivariate regression analysis, increasing age and female sex significantly predicted a lower total extensor CSA/VBA ratio (p < 0.001), while a longer duration of symptoms significantly predicted a greater total flexor/total extensor CSA ratio (p = 0.02). In patients undergoing single-level corpectomy, graft subsidence had a positive correlation with SACF in all patients (p < 0.05), irrespective of the preoperative segmental angle and curvature, while in patients undergoing 2-level corpectomy, graft subsidence demonstrated such a correlation only in the subgroup with lordotic curvatures (p = 0.02). Among the muscle area ratios, the DF/DE ratio demonstrated a negative correlation with SACF in the subgroup with preoperative straight or kyphotic segmental angles (p = 0.04 in the single corpectomy group, p = 0.01 in the 2-level corpectomy group). There was no correlation of any of the muscle ratios with change in Nurick grade.

Conclusions

Patients with CSM demonstrate significant atrophy in all the flexor and extensor paraspinal muscles, and also suffer a reduction in the protective effect of a strong DF/DE CSA ratio. Worsening of this ratio significantly correlates with greater segmental kyphotic change in some patients. A physiological mechanism based on DF dysfunction is discussed to elucidate these findings that have implications in preventive physiotherapy and rehabilitation of patients with CSM. Considering that the influence of a muscle ratio was significant only in patients with hypolordosis, a subgroup that is known to have facetal ligament laxity, it may also be postulated that ligamentous support supersedes the influence of paraspinal muscles on postoperative sagittal alignment in CSM.

How I do it : anterior clinoidectomy and optic canal unroofing for microneurosurgical management of ophthalmic segment aneurysms

BACKGROUND

Power drilling commonly used for anterior clinoidectomy and optic canal unroofing can result in thermal injury to the optic nerve.

METHODS

The authors describe an intradural "limited drill" technique of anterior clinoidectomy and optic canal unroofing for microneurosurgical management of ophthalmic segment aneurysms, where optic canal unroofing is done with 1 mm Kerrison punch and the use of the power drill is restricted to anterior clinoidectomy to avoid thermal injury to the optic nerve. The optic nerve, internal carotid artery (ICA), and aneurysm are covered with wet gelfoam pieces to prevent any inadvertent contact with the drill.

CONCLUSION

"Limited drill technique" is a safe and effective technique of anterior clinoidectomy and optic canal unroofing.

KEY POINTS

• Anterior clinoidectomy and optic canal unroofing is an important skull base technique required for safe clipping of the majority of ophthalmic segment aneurysms • Power drilling commonly used for optic canal unroofing can cause thermal injury to optic nerve • More than 2 mm free space is available around the optic nerve in the optic canal • Foot plate of 1 mm Kerrison punch can be safely introduced within a normal optic canal without causing mechanical injury to the optic nerve • Reflection of posteriorly based dural flap acts as a dural barrier, preventing direct contact of drill bit to optic nerve, internal carotid artery and aneurysm during drilling • Entanglement of cottonoids to rotating drill bit is a major problem in intradural anterior clinoidectomy • Wet gelfoam pieces do not get entangled to the rotating drill bit • Structures surrounding the area of drilling can be covered with wet gel foam pieces to prevent direct contact of the drill to neurovascular structures • Opened cisterns can be covered with wet gelfoam pieces during drilling to prevent deposition of bone dust in the subarachnoid space • "Limited drill technique" of anterior clinoidectomy and optic canal unroofing is a safe and effective technique for the exposure of ophthalmic segment aneurysms.

Subgaleo-peritoneal shunt: An effective and safer alternative to lumboperitoneal shunt in the management of persistent or recurrent iatrogenic cranial pseudomeningoceles

Subgaleo-peritoneal (SP) shunting for pseudomeningoceles (PMCs) is an effective and safer alternative as compared to the lumboperitoneal (LP) shunt. SP shunting was done in six patients (14-60 years) with persistent or recurrent PMCs using the cranial (ventricular part) and the distal parts of a Chhabra shunt connected by a rigid connector without any intervening chamber or valve. Two patients had undergone a prior LP shunt that had failed. One patient was unsuitable for a LP shunt placement. The PMC subsided completely in all the patients following the SP shunt. In one patient, the shunt got displaced and required repositioning. None of the patients developed symptoms of over-drainage or any other complication. All patients were asymptomatic at a mean follow-up of 15 months. These results suggest that SP shunting is a safe, simple, and effective alternative to the traditional LP shunt in the management of persistent or recurrent cranial PMCs.

A sacral arachnoid cyst causing holocord syringomyelia

Spinal extradural arachnoid cysts (ACs) have an infrequent predilection for the sacrum. As with their counterparts in other regions of the spine, cysts in this location are mostly asymptomatic. Common presentations in symptomatic cases include pain in the low back or perineum, radiculopathy, and sphincteric dysfunction. The authors report a hitherto undescribed presentation in which the predominant symptoms are those related to an associated holocord syrinx. This 15-year-old boy presented with fluctuating, spastic paraparesis and a dissociated sensory loss in the trunk. Admission MR imaging of the spine showed an extradural AC from S-2 to S-4 and a holocord, nonenhancing syrinx. The patient underwent S-2 laminectomy, fenestration of the cyst, and partial excision of its wall. Intradural exploration revealed a normal-looking filum terminale and the absence of any dural communication with the cyst. At a follow-up visit 6 months after surgery, his motor and sensory deficits had resolved. Follow-up MR imaging showed complete resolution of the syrinx in the absence of the sacral AC. This is the first report of a sacral extradural AC causing holocord syringomyelia. Because conventional theories of syrinx formation were not helpful in elucidating this case, a hypothesis is postulated to explain the clinicoradiological oddity.

Synchronous occurrence of a hemorrhagic hypothalamic hamartoma and a suprasellar teratoma

Hypothalamic hamartomas have been reported to coexist with lesions like Rathke's cleft cyst and arachnoid cysts in the suprasellar or temporo-sylvian regions. This is the first report in indexed literature describing its association with a suprasellar teratoma. A 7-year-old girl presented with long-standing precocious puberty and generalized tonic-clonic seizures and recent-onset raised intracranial pressure. MRI done prior to the onset of symptomatic raised intracranial pressure revealed 2 distinct lesions in the suprasellar region. One was a midline, pedunculated lesion arising from the hypothalamus, with evidence of an old bleed within it. A separate lesion, with a wide base near the tuberculum sellae and a posteriorly directed conical tip, was noted in an adjacent sagittal cut. CT scan done at the time of admission demonstrated a re-bleed in the suprasellar region with blood in the lateral and third ventricles and gross hydrocephalus. The child was taken up for a ventriculoperitoneal shunt followed by complete excision of the lesions. Histopathologic examination confirmed the pedunculated lesion to be a hypothalamic hamartoma with evidence of hemorrhage, and the other to be a mature teratoma. Postoperative MRI confirmed complete excision of both the lesions. The child reported regression of precocious puberty and remained seizure-free until the last follow-up 6 months after surgery. A hypothesis based on a dysontogenetic mechanism is discussed to explain the unusual occurrence of the dual, seemingly unrelated pathologies. Hemorrhage into the hamartoma was an added oddity in this case.

Outcome after hemorrhage following Gamma Knife surgery for cerebral arteriovenous malformations

Object

Although the effects of Gamma Knife surgery (GKS) on the risk of hemorrhage are poorly understood, a certain subset of patients does suffer bleeding after GKS. This study was undertaken to analyze the outcome of patients sustaining hemorrhage after GKS; it is the most feared complication of radiosurgical management of cerebral arteriovenous malformations (AVMs).

Methods

Between May 1997 and June 2006, 494 cerebral AVMs in 489 patients were treated using a Leksell Gamma Knife Model B, and follow-up evaluations were conducted until June 2007 at the All India Institute of Medical Sciences in New Delhi. Fourteen patients who sustained a hemorrhage after GKS formed the study group. In most of these patients conservative management was chosen.

Results

The mortality rate was 0% and there was a 7% risk of sustaining a severe deficit following rebleeding after GKS. None of the patients sustained rebleeding after complete obliteration. Patients with Spetzler-Martin Grade III or less had increased chances of hemorrhage after GKS (p < 0.002). The presence of deep venous drainage, aneurysm, venous hypertension, or periventricular location on angiography was common in patients with hemorrhage after GKS.

Conclusions

The risk of hemorrhage that remains following GKS for cerebral AVMs is highest in the 1st year after treatment. The present study showed a relatively good outcome even in cases with hemorrhage following GKS, with no deaths and minimal morbidity, further substantiating the safety and efficacy of the procedure.

Gross total excision of pediatric giant cystic craniopharyngioma with huge retroclival extension to the level of foramen magnum by anterior trans petrous approach: report of two cases and review of literature

PURPOSE

Craniopharyngiomas with a large posterior fossa extension beyond the level of the foramen magnum are very rare and usually removed in two stages. The objective of this paper is to report that such rare cases of giant cystic predominantly retrochiasmatic retroclival craniopharyngiomas can be completely excised by an anterior transpetrous approach in a single stage.

MATERIALS AND METHODS

The first case was a 6-year-old boy who presented with a 1-year history of recurrent episodes of seizures, headache, and vomiting. The second case was a 10-year-old girl who presented with history of headache, visual deterioration, and left-side hemiparesis for one and half years. Preoperative computed tomography (CT) and magnetic resonance imaging (MRI) in both these patients revealed a giant sellar suprasellar cystic lesion with areas of calcification and the lesion was predominantly retrochiasmatic with a huge retroclival posterior fossa extension down to the level of the C1 vertebra and laterally to the cerebellopontine angle. Gross total excision of both suprasellar and posterior fossa extensions could be done in both the patients through an anterior transpetrous transtentorial approach (Kawase's approach).

RESULTS

Postoperative imaging (MRI/CT) revealed no obvious evidence of residual tumor. The first patient had right hemiparesis from which he recovered completely. The second patient died suddenly on postoperative day 4 after initial uneventful postoperative period, and the exact cause of death is not known.

CONCLUSION

Giant cystic craniopharyngiomas, which are predominantly retrochiasmatic and associated with huge retroclival posterior fossa extensions, can be removed in single stage by Kawase's approach.

Gamma Knife surgery for intracranial arteriovenous malformations in children: a retrospective study in 103 patients

OBJECT

This retrospective study was designed to study the outcome in children with intracranial arteriovenous malformations (AVMs) treated with Gamma Knife surgery (GKS).

METHODS

One hundred and forty-two children were treated with GKS at the authors' institution between April 1997 and March 2006; of these, 103 patients with a mean follow-up of 26.4 months (range 6-96 months) were included. The mean age at presentation was 13.9 years (range 3-18 years). Eighty-six (83%) patients presented with hemorrhage. In 57 children the AVMs were Spetzler-Martin Grade I or II, and in 46 the AVMs were Grades III, IV, or V. The mean volume of the AVMs was 2.4 ml (range 0.04-23.3 ml). The mean marginal dose administered was 24.4 Gy (range 15-27 Gy). Follow-up angiography was advised at 2 years after GKS and yearly thereafter. In patients with residual AVMs, follow-up angiography was advised yearly until 4 years after GKS. If residual AVM was present, even on a follow-up angiogram obtained 4 years postsurgery, the GKS was considered a failure.

RESULTS

Complete obliteration of the AVM was documented in 34 (87%) of the 39 patients with complete angiographic follow-up. The 3- and 4-year actuarial rates of nidus obliteration were 66 and 86% respectively. Three patients (2.9%) experienced bleeding during the latency period, and symptomatic radiation-induced edema was noted in four patients (3.8%). A significantly higher incidence of radiation edema was noted in patients with AVM volumes greater than 3 ml and in patients with Spetzler-Martin Grade IV and V AVMs.

CONCLUSIONS

Gamma Knife radiosurgery is an effective modality for the treatment of intracranial AVMs in children, yielding high obliteration rates and low complication rates.

Spontaneous thrombosis of giant cavernous internal carotid artery aneurysm in a neonate. Case report and review of the literature

Neonatal intracranial aneurysms are rare, with only 20 cases being reported in the literature. No case of spontaneous resolution of a giant intracranial cavernous segment aneurysm in a neonate is reported till date. The authors describe a 3-week-old male child who presented with a left-sided tonic seizure episode and was diagnosed as having a right-sided giant cavernous internal carotid artery aneurysm. The aneurysm was found to be totally thrombosed on angiography done before planning definitive treatment. The child is doing well at 2 years of follow-up. Spontaneous thrombosis, an exceptionally rare but fortunate outcome in a rare case of giant neonatal internal carotid artery aneurysm, has led the authors to report this case. The need of repeat imaging or angiography should be considered to rule out this rare outcome, more so if there is any delay between the ictus and treatment.

Eumycetoma presenting as a cerebellopontine angle mass lesion

Eumycetoma in the cerebellopontine angle region is extremely uncommon with no case being reported as per an extensive review of the literature by the authors. The authors report a case of cerebellopontine angle eumycetoma in a young female managed by subtotal decompression and antifungal treatment. The pre-operative diagnosis of eumycetoma in this location is extremely difficult and the role of histopathology is very important to characterize this uncommon lesion. The prognosis of this bizarre pathology is dismal despite all treatment modalities as compared to the usual tumors of the cerebellopontine angle that generally have a favorable outcome.