Neena I. Marupudi, Sandeep Sood, Arlene Rozzelle, and Steven D. Ham
Cranial vault expansion is performed in pediatric patients with craniosynostosis to improve head shape. Another argument for performing total cranial vault reconstruction is the potential reduction in the harmful effects of elevated intracranial pressure (ICP) that are associated with craniosynostosis. Alternatively, molding helmets have been shown to improve the cranial index (CI) in patients with sagittal synostosis without surgery. However, it is unknown if the use of molding helmets without surgery contributes to adverse changes in ICP. The effect of molding helmets on ICP and CI in patients with sagittal synostosis was investigated.
A prospective cohort study of 24 pediatric patients with sagittal synostosis who planned to undergo total cranial reconstruction was performed from 2011 to 2014 at the Children's Hospital of Michigan. A preoperative molding helmet was used in 13 patients, and no molding helmet was used in 11 patients. End-tidal carbon dioxide, patient positioning, level of sedation, type of anesthetic, and the monitoring site at the time of intraoperative recording were regulated and standardized to establish the accuracy of the ICP readings. CI and head circumference were monitored for each patient.
The mean duration of the preoperative use of the molding helmet was 17 weeks (range 7–37 weeks). Under controlled settings, the average intraoperative ICP was 7.2 mm Hg (range 2–18 mm Hg) for patients treated with a preoperative molding helmet and 9.5 mm Hg (range 2–22 mm Hg) for patients with no preoperative molding helmet. ICP was not significantly different between the 2 groups, suggesting that the use of a molding helmet in this population is safe. The average CI at the time of helmet placement was 0.70 (range 0.67–0.73), and this improved to an average of 0.74 (range 0.69–0.79) after using the molding helmet for a mean of 17 weeks.
ICPs were not significantly different with the use of a preoperative molding helmet, refuting the prevailing thought that molding helmets would be detrimental in children who have craniosynostosis. The use of molding helmet in this population of patients improves head shape and does not adversely affect ICP.
Sandeep Sood, Neena I. Marupudi, Eishi Asano, Abilash Haridas, and Steven D. Ham
Corpus callosotomy and hemispherotomy are conventionally performed via a large craniotomy with the aid of a microscope for children with intractable epilepsy. Primary technical considerations include completeness of disconnection and blood loss. The authors describe an endoscopic technique performed through a microcraniotomy for these procedures.
Four patients with drop attacks and 2 with intractable seizures related to a neonatal stroke underwent endoscopic complete corpus callosotomy and hemispherotomy, respectively. The surgeries were performed through a 2- to 3-cm precoronal microcraniotomy. Interhemispheric dissection to the corpus callosum was done using the standard technique. Subsequently, the bimanual technique with a suction device mounted on an endoscope was used to perform a complete corpus callosotomy, including interforniceal and anterior commissure disconnection. In patients who had hemispherotomy, the fornix was resected posteriorly and lateral disconnection was done by unroofing the temporal horn. Anteriorly, endoscopic corticectomy was done along the ipsilateral anterior cerebral artery to reach the bifurcation of the internal carotid artery to complete the anterior disconnection. Postoperative MRI and diffusion tensor imaging (DTI) of the brain were performed to confirm complete disconnection.
The procedure was accomplished successfully in all patients, with excellent visualization secured. None of the patients required a blood transfusion. Postoperative MRI and DTI confirmed completeness of the disconnection. Patients who underwent corpus callosotomy had complete resolution of drop attacks at a mean follow-up of 6 months, and patients who underwent hemispherotomy became seizure free.
Endoscopic corpus callosotomy and hemispherotomy are surgically feasible procedures associated with minimal blood loss, minimal risk, and excellent visualization.
Sandeep Sood, Neena I. Marupudi, and Steven D. Ham
P. Sarat Chandra and Manjari Tripathi
Neena I. Marupudi, Carolyn Harris, Tanya Pavri, Brenna Mell, Rasanjeet Singh, Steven D. Ham, and Sandeep Sood
Lumboperitoneal (LP) shunts have a role not only in pseudotumor cerebri, but also in patients with slit-like ventricles who are treated with CSF shunting on a chronic basis. Hesitation to utilize LP shunts is based on previous conventional beliefs including the tendency for overdrainage, difficulties accessing the shunt to tap or revise, and risk of progressive cerebellar tonsillar herniation. The authors hypothesized that the use of horizontal-vertical (HV) valves may reduce the risk of these complications, particularly overdrainage and development of Chiari malformation.
All pediatric cases involving patients treated with an LP shunt at the Children’s Hospital of Michigan were reviewed in this retrospective case series. A total of 143 patients with hydrocephalus were treated with LP shunts from 1997–2015 (follow-up range 8 months–8 years, median 4.2 years). Patients with pseudotumor cerebri underwent placement of an LP shunt as a primary procedure. In patients with slit ventricles from chronically treated hydrocephalus or repeated shunt malfunctions from proximal catheter obstruction, a lumbar drain was inserted to assess candidacy for conversion to an LP shunt. In patients who tolerated the lumbar drain and demonstrated communication of the ventricles with the spinal cisterns, treatment was converted to an LP shunt. All patients included in the series had undergone initial shunt placement between birth and age 16 years.
In 30% of patients (n = 43), LP shunts were placed as the initial shunt treatment; in 70% (n = 100), treatment was converted to LP shunts from ventriculoperitoneal (VP) shunts. The patients’ age at insertion of or conversion to an LP shunt ranged from 1 to 43 years (median 8.5 years). Of the patients with clear pre-LP and post-LP shunt follow-up imaging, none were found to develop an acquired Chiari malformation. In patients with pre-existing tonsillar ectopia, no progression was noted on follow-up MRIs of the brain in these patients after LP shunt insertion. In our LP shunt case series, no patient presented with acute deterioration from shunt malfunction.
Conversion to an LP shunt may minimize acute deterioration from shunt malfunction and decrease morbidity of repeated procedures in patients with chronically shunt-treated hydrocephalus and small ventricles. In comparison to previously published case series of LP shunt treatment, the use of LP shunts in conjunction with HV valves may decrease the overall risk of cerebellar tonsillar herniation. The use of an LP shunt may be an alternative in the management of slit ventricles when VP shunting repeatedly fails.
Daniel M. Sciubba, Joseph C. Noggle, Neena I. Marupudi, Carlos A. Bagley, Markus J. Bookland, Benjamin S. Carson Sr., Michael C. Ain, and George I. Jallo
Achondroplasia is a hereditary form of dwarfism caused by a defect in endochondral bone formation, resulting in skeletal abnormalities including short stature, shortened limb bones, macrocephaly, and small vertebral bodies. In the pediatric population, symptomatic spinal stenosis occurs at all spinal levels due to the abnormally narrow bone canal. In this study, clinical outcomes were assessed in children with achondroplasia after spinal canal decompression.
A retrospective review was conducted involving pediatric patients with heterozygous achondroplasia and symptomatic stenosis after decompressive procedures at the authors' institution within a 9-year period. Measured outcomes included resolution of symptoms, need for repeated surgery, presence of fusion, development of deformity, and complications.
Forty-four pediatric patients underwent a total of 60 decompressive procedures. The average patient age at surgery was 12.7 years (range 5–21 years). Forty-nine operations were performed for initial treatment of stenosis, and 11 were performed as revision surgeries on previously operated levels. A large proportion of patients (> 60%) required additional cervicomedullary decompressions, most often preceding the symptoms of spinal stenosis. Of the initial procedures, decompression locations included 32 thoracolumbar (65%), 10 lumbar (20%), four cervical (8%), two cervicothoracic (4%), and one thoracic (2%). Forty-three of the decompressive procedures (72%) included spinal fusion procedures. Of the 11 revisions, five were fusion procedures for progressive deformity at levels previously decompressed but not fused (all thoracolumbar), five were for decompressions of symptomatic junctional stenosis with extension of fusion, and one was for repeated decompression at the same level due to recurrence of symptomatic stenosis.
Decompression of the spinal canal in pediatric patients with achondroplasia can be accomplished safely with significant clinical benefit. Patients with a history of cervicomedullary compression may be at an increased risk of developing symptomatic stenosis prior to adolescence. Fusion procedures are recommended in patients with a large decompression overlying a thoracolumbar kyphosis to avoid progressive postoperative deformity.
Sulmaz Zahedi, Miles Hudson, Xin Jin, Richard Justin Garling, Jacob Gluski, Caden Nowak, Neena I. Marupudi, Paul Begeman, and Carolyn A. Harris
This investigation is aimed at gaining a better understanding of the factors that lead to mechanical failure of shunts used for the treatment of hydrocephalus, including shunt catheter-valve disconnection and shunt catheter fracture.
To determine the root cause of mechanical failure, the authors created a benchtop mechanical model to mimic mechanical stressors on a shunt system. To test shunt fracture, cyclical loading on the catheter-valve connection site was tested with the shunt catheter held perpendicular to the valve. Standard methods were used to secure the catheter and valves with Nurolon. These commercial systems were compared to integrated catheters and valves (manufactured as one unit). To test complete separation/disconnection of the shunt catheter and valve, a parallel displacement test was conducted using both Nurolon and silk sutures. Finally, the stiffness of the catheters was assessed. All mechanical investigations were conducted on shunts from two major shunt companies, assigned as either company A or company B.
Cyclical loading experiments found that shunts from company B fractured after a mean of 4936 ± 1725 cycles (95% CI 2990–6890 cycles), while those of company A had not failed after 8000 cycles. The study of parallel displacement indicated complete disconnection of company B’s shunt catheter-valve combination using Nurolon sutures after being stretched an average 32 ± 5.68 mm (95% CI 25.6–38.4 mm), whereas company A’s did not separate using either silk or Nurolon sutures. During the stiffness experiments, the catheters of company B had statistically significantly higher stiffness of 13.23 ± 0.15 N compared to those of company A, with 6.16 ± 0.29 N (p < 0.001).
Mechanical shunt failure from shunt catheter-valve disconnection or fracture is a significant cause of shunt failure. This study demonstrates, for the first time, a correlation between shunt catheters that are less mechanically stiff and those that are less likely to disconnect from the valve when outstretched and are also less likely to tear when held at an angle from the valve outlet. The authors propose an intervention to the standard of care wherein less stiff catheters are trialed to reduce disconnection.