A new shunt for obstructive hydrocephalus: ventricle-Sylvian fissure shunt A preliminary report.

Cerbrospinal fluid (CSF) pathway studies have revealed that after egressing from the fourth ventricle reaches the basal supra sellar cistern and ultimately the sylvian cisterns from where the CSF travels over the cerebral convexity subarachnoid space to reach the superior saggital sinus and enters the blood stream. Diverting CSF from the lateral ventricle with a shunt catheter to the sylvian cistern can be an option to treat obstructive hydrocephalus. 2 patients underwent this procedure of diverting CSF from the lateral ventricle with a shunt catheter (Chabbra, India) to the sylvian cistern successfully and had immediate relief of symptoms of raised intracranial pressure. Additional 4 patients had relief for 3mths to 6 mths and are under follow up. Though preliminary results seem logical and promising, more cases and longer follow-up is required to consider this shunt operation as an option in treatment of obstructive hydrocephalus.

Unstable odontoid fractures: technical appraisal of anterior extrapharyangeal open reduction internal fixation for irreducible unstable odontoid fractures. Patient series.

BACKGROUND: Displaced odontoid fractures that are irreducible with traction and have cervicomedullary compression by the displaced distal fracture fragment or deformity caused by facetal malalignment require early realignment and stabilization. Realignment with ultimate solid fracture fusion and atlantoaxial joint fusion, in some situations, are the aims of surgery. Fifteen such patients were treated with direct anterior extrapharyngeal open reduction and realignment of displaced fracture fragments with realignment of the atlantoaxial facets, followed by a variable screw placement (VSP) plate in compression mode across the fracture or anterior atlantoaxial fixation (transarticular screws or atlantoaxial plate screw construct) or both. OBSERVATIONS: Anatomical realignment with rigid fixation was achieved in all patients. Fracture fusion without implant failure was observed in 100% of the patients at 6 months, with 1 unrelated mortality. Minimum follow-up has been 6 months in 14 patients and a maximum of 3 years in 4 patients, with 1 unrelated mortality. LESSONS: Most irreducible unstable odontoid fractures can be anatomically realigned by anterior extrapharyngeal approach by facet joint manipulation. Plate (VSP) and screws permit rigid fixation in compression mode with 100% fusion. Any associated atlantoaxial instability can be treated from the same exposure.

Basilar Invagination: Surgical Treatment by Novel Anterior Implant.

Introduction: Anterior retropharyngeal realignment, distraction, and atlantoaxial fixation are an option for the treatment of symptomatic basilar invagination (BI). The anterior implants for distraction and fixation for atlantoaxial joints are still evolving. We share our experience using a novel implant which can easily, safely, and rigidly fix both lateral masses to the body of the axis. Methods: After exposing both the atlantoaxial joints anteriorly, the joints were prepared, distracted with wedge shaped autologous tricorticate bone grafts and realigned to correct the cervicomedullary strain. The atlantoaxial joints were fixed using a novel titanium plate by passing screws upwards and laterally into the lateral masses of the atlas and centrally into the body of the axis. Post-operative imaging showed effective correction of BI and atlantoaxial dislocation. Post-operative dynamic X-ray images confirmed maintenance of rigid fixation at 6 months. Conclusion: This new plate screw construct is safe, easy, cost-efficient, and biomechanically appealing option for the treatment of symptomatic BI.

Posterior atlantoaxial fixation with new subfacetal axis screw trajectory avoiding vertebral artery with customized variable screw placement plate and screws to enhance biomechanics of fixation.

Fixation for atlantoaxial dislocation is a challenging issue, and posterior C1 lateral mass and C2 pars-pedicle screw plate-rod construct is the standard of care for atlantoaxial instability. However, vertebral artery injury remains a potential complication. Recent literature has focused on intraoperative navigation, the O-arm, 3D printing, and recently use of robots for perfecting the trajectory and screw position to avoid disastrous injury to the vertebral artery and enhance the rigidity of fixation. These technological advances increase the costs of the surgery and are available only in select centers in the developed world. Review of the axis bone anatomy and study of the stress lines caused by weight transmission reveal that the bone below the articular surface of the superior facet is consistently dense as it lies along the line of weight transmission A new trajectory for the axis screw 3-5 mm below the midpoint of the facet joint and directed downward and medially avoids the course of the vertebral artery and holds the axis rigidly. Divergent screw constructs are biomechanically stronger. Variable screw placement (VSP) plates with long shaft screws permit manipulation of the vertebrae and realignment of the facets to the correct reduced position with fixation in the compression mode. The video can be found here: https://youtu.be/E1msiKjM-aA.

Anterior retropharyngeal cage distraction with atlantoaxial plate-screw fixation for basilar invagination with atlantoaxial dislocation.

The unilateral submandibular anterior retropharyngeal approach in properly selected patients offers the possibility to expose both atlantoaxial joints adequately, abrade the endplates, and graft the joint spaces. The supine position in extension permits the use of wedge-shaped cages, which reduce the invagination and correct the dislocation. Adequate bone stock is available to rigidly fix the joints using an anterior plate-screw construct without any risk to the vertebral arteries. The approach preserves the posterior tension band and the C2 root. The technique is quick, simple, and safe, and results in solid fusion of the joints over time. The video can be found here: https://youtu.be/tT6j3Czy6tc.

Anterior Retropharyngeal Cage Distraction and Fixation for Basilar Invagination: "The Wedge Technique".

OBJECTIVE: Surgery is indicated for basilar invagination (BI) in symptomatic patients. In many patients, symptoms and signs occur due to an upward-migrated and malaligned odontoid with fixed or mobile atlantoaxial instability. Posterior distraction and fixation of the atlantoaxial joints has evolved to become the standard of care, but has some inherent morbidity. In this study, we propose that the unilateral anterior submandibular retropharyngeal approach with customized wedge-shaped titanium cages inserted into both atlantoaxial joints and anterior atlantoaxial fixation with a plate screw construct is a safer and easier option in many cases of BI. METHODS: From February 2014 to February 2019, 52 patients (age range, 15-78 years; 40 males and 12 females) with symptomatic BI with atlantoaxial dislocation and minimal sagittal facetal inclination and only mild Chiari malformation without syringomyelia were offered anterior submandibular retropharyngeal atlantoaxial distraction and fixation surgery. RESULTS: Neurological improvement occurred in 80% of patients, while the neurological status of 20% remained unchanged. No patients worsened, and no major complications or mortality was observed. CONCLUSION: In properly selected cases of symptomatic BI, anterior wedge cage distraction with anterior atlantoaxial fixation is a safe and simple option.

Anterior retropharyngeal plate screw fixation with bilateral anterior transarticular screws for odontoid fractures ... a new comprehensive technique.

INTRODUCTION: A certain group of odontoid fractures (Anderson and D' Alonzo Type-2) are usually offered surgical treatment. Common surgical option is an anterior odontoid screw. Some of the fractures are not suitable for anterior odontoid screw (anterior oblique, displaced distal fragments and those with atlantoaxial instability) and these are usually offered posterior transarticular screws (Magerl's) or posterior atlantoaxial screw rod/plate fixation (Goel-Harms technique). Posterior surgery involves atlantoaxial fixation with an indirect attempt to reduce and fuse the fracture . Posterior surgery has a risk of injury to the vertebral arteries, hemorrhage from the paravertebral venous plexus and the C2 root ganglion. METHODS: A direct anterior submandibular retropharyangeal approach with open reduction and fixation (ORIF) using a customized variable screw placement (VSP) plate was used to realign and fix the fracture fragments in compression mode under direct vision. Twenty patients of type-II odontoid fractures (unsuitable for anterior odontoid screw) underwent an anterior retropharyngeal approach with anterior variable screw position (VSP) plate and screw fixation and eight amongst them, who had associated atlantoaxial instability underwent additional bilateral anterior transarticular screws. RESULTS: All patients treated by this technique had 100% fracture site bone union without any implant failure. Longest follow-up has been for 3 years. CONCLUSION: Anterior retropharyangeal approach allows direct fracture fragment realignment under vision with an opportunity to fix in compression mode using the VSP plate, which ensures early fusion across the type-II odontoid fracture. Any associated instability can be treated by additional bilateral anterior transarticular screws. The approach is simple and safe without any risk to the vertebral arteries and biomechanically appealing.

Craniovertebral fixation a new technique of occipital - cervical fixation.

BACKGROUND: Craniovertebral instability following transoral odontoid excision is usually treated by posterior occipital-cervical fixation using occipital plate and cervical lateral mass fixation with screw rod construct. A patient previously operated for basilar invagination had postoperative infection of both the transoral wound and the posterior implant site which needed removal of the posterior implant earlier. CLINICAL PRESENTATION: The patient presented with severe neck pain, myelopathy, and chronic discharging sinus in the posterior lower aspect the previous neck surgery wound. Reimaging revealed incomplete odontoid excision. He underwent repeat transoral odontoid excision. Treatment of the instability needed occipitocervical fixation avoiding, the atlas, axis (weakened by infection and previous implants), and the infected posterior cervical wound. A new technique using a customized plate rod construct, fixed anteriorly to the mid cervical vertebrae (by a standard mid cervical exposure) with the rods contoured to reach posteriorly through the safe paraspinal corridor and connected with domino connectors to occipital plate rods fixed on either side of midline by additional posterior exposure avoiding the midline scar was planned and executed successfully. CONCLUSION: This construct transfers the weight of the cranium to the cervical vertebral bodies along the physiological line of weight transmission and can be considered for distraction and reduction of basilar invagination with atlantoaxial dislocation. The technique seems to be safe and reproducible, but will need to tested over time with more cases.

Lateral Ventricle to Sylvian Fissure Shunt for Obstructive Hydrocephalus: First Report.

Cerebrospinal fluid (CSF) pathway studies have revealed that the CSF secreted from the choroid plexus of the ventricles after egressing from the fourth ventricle reaches the basal suprasellar cistern and ultimately the sylvian cisterns. From the sylvian cistern, the CSF travels over the cerebral convexity subarachnoid space to reach the superior sagittal sinus and enters the bloodstream. Diverting CSF from the lateral ventricle with a shunt catheter to the sylvian cistern can be an option to treat obstructive hydrocephalus. An adult patient with posttraumatic hydrocephalus with contraindications to ventriculoperitoneal and ventriculoatrial shunt placement underwent this procedure of diverting CSF from the lateral ventricle to the sylvian cistern successfully, and he had immediate relief of symptoms of raised intracranial pressure. Although preliminary results seem logical and promising, more cases and longer follow-up is required to consider this shunt operation an option in the treatment of obstructive hydrocephalus.

Anterior facetal realignment and distraction for atlanto-axial subluxation with basilar invagination . a technical note.

Unilateral anterior retropharyngeal approach was used in a case of basilar invagination with atlanto-axial instability. This approach provided easy access to both atlanto-axial joints. Wedge-shaped titanium cages were used to distract the joints and reduce the basilar invagination. Titanium plates with screws were used to fix the lateral mass of atlas with the body of axis, bilaterally. The anterior atlanto-axial joint distraction procedure has not been described in literature before seems to be an easy option in selected cases of craniovertebral anomalies and needs to be investigated by more surgeons.

New entry point for C2 screw, in posterior C1-C2 fixation (Goel-Harm's technique) significantly reducing the possibility of vertebral artery injury.

OBJECTIVE: To reduce the chance of vertebral artery injury in posterior C1 lateral mass and C2 pedicle/pars screw-rod fixation (Goel-Harms technique ). METHOD: 49 patients, 30 males and 19 females, 12years - 82 years, underwent posterior C1-C2 fixation from February 2007 till June2013. A new entry point for the posterior C2 screw, 3mm below the midpoint of the C1-C2 joint which is directed medially and downwards into the C2 body , probably avoids the vertebral artery. As the screw now bypasses the pedicle/ pars , the chance of injuring the vertebral artery is probably reduced. RESULTS: No case of intra-operative vertebral artery injury. CONCLUSION: The new technique of C2 screw fixation allows rigid immobilization of the C1-C2 joint without significant risk of vertebral artery injury.