Excision of petroclival meningiomas remains a surgical challenge. Extradural anterior petrosectomy is widely used as a skull base approach for these tumors; however, this approach has significant procedure-related morbidity. The authors describe an alternative technique of tailored intradural petrosectomy for removal of petroclival meningiomas. This technique was used successfully in 5 patients. Gross-total or near-total resection was possible in 2 patients, whereas a subtotal removal was achieved in 3 patients, without significant morbidity. The petrous drilling was tailored depending on the extent of tumor. Transsylvian intradural anterior petrosectomy is a safe approach for petroclival meningiomas. This approach avoids problems related to subtemporal retraction and rationalizes the degree of bone drilling.
Sunil Kumar Gupta and Pravin Salunke
Pravin Salunke, Ravi Garg, Ankur Kapoor, Rajesh Chhabra, and Kanchan K. Mukherjee
Contralateral subdural hygromas are occasionally observed after decompressive craniectomies (DCs). Some of these hygromas are symptomatic, and the etiology and management of these symptomatic contralateral subdural collections (CLDCs) present surgical challenges. The authors share their experience with managing symptomatic CLSDCs after a DC.
During a 10-month period, 306 patients underwent a DC. Of these patients, 266 had a head injury, 25 a middle cerebral artery infarction (that is, a thrombotic stroke), and 15 an infarction due to a vasospasm (resulting from an aneurysmal subarachnoid hemorrhage [SAH]). Seventeen patients (15 with a head injury and 2 with an SAH) developed a CLSDC, and 7 of these patients showed overt symptoms of the fluid collection. These patients were treated with a trial intervention consisting of bur hole drainage followed by cranioplasty. If required, a ventriculo- or thecoperitoneal shunt was inserted at a later time.
Seven patients developed a symptomatic CLSDC after a DC, 6 of whom had a head injury and 1 had an SAH. The average length of time between the DC and CLSDC formation was 24 days. Fluid drainage via a bur hole was attempted in the first 5 patients. However, symptoms in these patients improved only temporarily. All 7 patients (including the 5 in whom the bur hole drainage had failed and 2 directly after the DC) underwent a cranioplasty, and the CLSDC resolved in all of these patients. The average time it took for the CLSDC to resolve after the cranioplasty was 34 days. Three patients developed hydrocephalus after the cranioplasty, requiring a diversion procedure, and 1 patient contracted meningitis and died.
Arachnoid tears and blockage of arachnoid villi appear to be the underlying causes of a CLSDC. The absence of sufficient fluid pressure required for CSF absorption after a DC further aggravates such fluid collections. Underlying hydrocephalus may appear as subdural collections in some patients after the DC. Bur hole drainage appears to be only a temporary measure and leads to recurrence of a CLSDC. Therefore, cranioplasty is the definitive treatment for such collections and, if performed early, may even avert CLSDC formation. A temporary ventriculostomy or an external lumbar drainage may be added to aid the cranioplasty and may be removed postoperatively. Ventriculoperitoneal or thecoperitoneal shunting may be required for patients in whom a hydrocephalus manifests after cranioplasty and underlies the CLSDC.
Pravin Salunke, Sameer S. Futane, and Ashish Aggarwal
Although uncommon, variations in split cord malformation (SCM) have been described. However, a combination of SCM Type II and dorsal lipomas has not been reported.
The authors describe the case of a 6-year-old girl who presented with a 1-year history of spastic paraparesis associated with a lipomatous swelling on her lower back. Radiology revealed a Type II SCM with a dorsal lipoma at that level. Intraoperatively, the authors observed a dorsal lipoma for each hemicord; these were excised, and the septum causing the split was cut.
Premature separation of the cutaneous and neural ectoderm is predetermined for each neural fold, and a split at this level would give rise to SCM with twin dorsal lipomas, one for each hemicord.
Manjul Tripathi, Pravin Salunke, and Kanchan Kumar Mukherjee
Pravin Salunke, Sushanta K. Sahoo, Arsikere N. Deepak, Mandeep S. Ghuman, and Niranjan K. Khandelwal
The cause of irreducibility in irreducible atlantoaxial dislocation (AAD) appears to be the orientation of the C1–2 facets. The current management strategies for irreducible AAD are directed at removing the cause of irreducibility followed by fusion, rather than transoral decompression and posterior fusion. The technique described in this paper addresses C1–2 facet mobilization by facetectomies to aid intraoperative manipulation.
Using this technique, reduction was achieved in 19 patients with congenital irreducible AAD treated between January 2011 and December 2013. The C1–2 joints were studied preoperatively, and particular attention was paid to the facet orientation. Intraoperatively, oblique C1–2 joints were opened widely, and extensive drilling of the facets was performed to make them close to flat and parallel to each other, converting an irreducible AAD to a reducible one. Anomalous vertebral arteries (VAs) were addressed appropriately. Further reduction was then achieved after vertical distraction and joint manipulation.
Adequate facet drilling was achieved in all but 2 patients, due to VA injury in 1 patient and an acute sagittal angle operated on 2 years previously in the other patient. Complete reduction could be achieved in 17 patients and partial in the remaining 2. All patients showed clinical improvement. Two patients showed partial redislocation due to graft subsidence. The fusion rates were excellent.
Comprehensive drilling of the C1–2 facets appears to be a logical and effective technique for achieving direct posterior reduction in irreducible AAD. The extensive drilling makes large surfaces raw, increasing fusion rates.
Pravin Salunke, Manish Sharma, Harsimrat Bir Singh Sodhi, Kanchan K. Mukherjee, and Niranjan K. Khandelwal
Patient age at presentation with congenital atlantoaxial dislocation (CAAD) is variable. In addition, the factors determining irreducibility or reducibility in these patients remain unclear. The facets appear to contribute to the stability of the joint, albeit to an unknown extent. The objective of this paper was to study the characteristics of C1–2 facets in these patients and their bearing on the clinicoradiological presentation and management.
Twenty-four patients with CAAD were studied. Fifteen patients had irreducible CAAD (IrAAD); 3 of these patients experienced incomplete reduction after traction, and 9 had reducible CAAD (RAAD). The images (CT scans of the craniovertebral junction in a neutral position) obtained in the parasagittal, axial, and coronal planes were studied with respect to the C1–2 facets and were compared with 32 control scans. The inferior sagittal and coronal C-1 facet angles were measured. The lordosis of the cervical spine (cervical spine angle calculated on radiographs of the cervical spine, neutral view) in these patients was compared with normal. The management of these patients is described.
The inferior sagittal C-1 facet angle and at least one coronal angle in patients with IrAAD were significantly acute compared with those in patients with RAAD and the control population. A significant correlation was found between age and the acuteness of the inferior sagittal C-1 facet angle (that is, the more acute the angle, the earlier the presentation). The lordosis of the cervical spine was exaggerated in patients with IrAAD. Three patients with IrAAD who had smaller acute angles experienced a partial reduction after traction and a complete reduction after intraoperative distraction of the facets, thereby avoiding a transoral procedure. An inferior sagittal C-1 facet angle of more than 150° in the sagittal plane predicted reducibility. Drilling a wedge off the facet in the sagittal plane to make the inferior sagittal C-1 facet angle 150° can reduce the C1–2 joint intraoperatively by posterior approach alone.
The acuteness of the inferior C-1 sagittal facet angles possibly determines the age at presentation and reducibility. The coronal angles determine the telescoping of C-2 within C-1. Patients with IrAAD can be treated using a posterior approach alone with the exception of those with extremely acute angles or a retroflexed dens. The exaggerated lordosis of the cervical spine in these patients is a compensatory phenomenon.
Pravin Salunke, Sushanta K. Sahoo, Ramesh Doddamani, Chirag K. Ahuja, and Kanchan K. Mukherjee
Posttraumatic true irreducible C1–2 lateral dislocation is rare. The mechanism of injury is likely to be different for this kind of dislocation. The management of such an injury and the technique for direct posterior reduction remain unclear because of its rarity. The authors describe the case of a 34-year-old man who sustained injury in a vehicular accident, leading to neck pain. Radiological studies revealed fixed right lateral and posterior C1–2 dislocation. Direct posterior open reduction was achieved by distracting the facets and rotating them in a counterclockwise direction. Care was taken to avoid direct or indirect injury to the vertebral arteries. Segmental C1–2 fusion was performed. Distraction with lateral extension injury possibly gives rise to this unique fracture dislocation. Preoperative imaging including angiography for vertebral arteries helps in defining the cause of fixity and in surgical planning. Direct posterior reduction is possible in such fixed C1–2 lateral dislocation, circumventing transoral surgery—provided the facets are preserved.
Arsikere N. Deepak, Pravin Salunke, Sushanta K. Sahoo, Prashant K. Prasad, and Niranjan K. Khandelwal
The current management of atlantoaxial dislocation (AAD) focuses on the C1–2 joints, commonly approached through a posterior route. The distinction between reducible AAD (RAAD) and irreducible AAD (IrAAD) seems to be less important in modern times. The roles of preoperative traction and dynamic radiographs are questionable. This study evaluated whether differentiating between the 2 groups is important in today's era.
Ninety-six consecutive patients with congenital AAD (33 RAAD and 63 IrAAD), who underwent surgery through a posterior approach alone, were studied. The preoperative and follow-up clinical statuses for both groups were studied and compared using Japanese Orthopaedic Association (JOA) scores. The radiological findings of the 2 groups were compared, and the intraoperative challenges described.
A poor preoperative JOA score (clinical status) was seen in one-fifth of patients with IrAAD, although the mean JOA score was nearly similar in the RAAD and IrAAD groups. There was significant improvement in follow-up JOA score in both groups. However, segmentation defects (such as an assimilated arch of the atlas and C2–3 fusion) and anomalous vertebral arteries were found significantly more often in cases of IrAAD compared with those of RAAD. Os odontoideum was commonly seen in the RAAD group. The C1–2 joints were acute in IrAAD compared with RAAD. Preoperative traction in IrAAD resulted in vertical distraction and improvement in clinical and respiratory status. Surgery for IrAAD required much more drilling and manipulation of the C1–2 joints while safeguarding the anomalous vertebral artery.
Bony and vascular anomalies were much more common in patients with IrAAD, which made surgery more challenging than it was in RAAD despite similar approaches. An irreducible dislocation seen on preoperative radiographs made surgeons aware of difficulties that were likely to be encountered and helped them to better plan the surgery. Distraction achieved through preoperative traction reaffirmed the feasibility of intraoperative reduction. This made the differentiation between the 2 groups and the use of preoperative traction equally important.
Pravin Salunke, Sameer Futane, Sushant K. Sahoo, Mandeep S. Ghuman, and Niranjan Khandelwal
Stabilization of the craniovertebral junction (CVJ) by using lateral masses requires extensive dissection. The vertebral artery (VA) is commonly anomalous in patients with congenital CVJ anomaly. Such a vessel is likely to be injured during dissection or screw placement. In this study the authors discuss the importance of preoperative evaluation and certain intraoperative steps that reduce the chances of injury to such vessels.
A 3D CT angiogram was obtained in 15 consecutive patients undergoing surgery for congenital atlantoaxial dislocation. The course of the VA and its relationship to the C1–2 facets was studied in these patients. The anomalous VA was exposed intraoperatively, facet surfaces were drilled in all, and the screws were placed according to the disposition of the vessel.
A skeletal anomaly was found in all 10 patients who had an anomalous VA. Four types of variations were noted: 1) the first intersegmental artery in 5 patients (bilateral in 1); 2) fenestration of VA in 1 patient; 3) anomalous posterior inferior cerebellar artery crossing the C1–2 joint in 1 patient; and 4) medial loop of VA in 5 patients. The anomalous vessel was dissected and the facet surfaces were drilled in all. The C-1 lateral mass screw was placed under vision, taking care not to compromise the anomalous vessel, although occipital screws or sublaminar wires were used in the initial cases. A medial loop of the VA necessitated placement of transpedicular or C-2 lateral mass screws instead of pars interarticularis screws. The anomalous vessel was injured in none.
Preoperative 3D CT angiography is a highly useful method of imaging the artery in patients with CVJ anomaly. It helps in identifying the anomalous VA or its branch and its relationship to the C1–2 facets. The normal side should be surgically treated and distracted first because this helps in opening the abnormal side, aiding in dissection. In the posterior approach the C-2 nerve root is always encountered before the anomalous vessel. The defined vascular anatomy helps in choosing the type of screw. The vessel should be mobilized so as to aid the drilling of facets and the placement of screws and spacers under vision, avoiding its injury (direct or indirect) or compression. With these steps, C1–2 (short segment) rigid fusion can be achieved despite the presence of anomalous VA.