The surgical treatment of refractory epilepsy has evolved as new innovations have been created. Disconnective procedures such as hemispherectomy have evolved. Presently, hemispherotomy has replaced hemispherectomy to reduce complication rates while maintaining good seizure control. Several disconnective techniques have been described including the Rasmussen, vertical, and lateral approaches. The lateral approach, or periinsular hemispherectomy, was derived from modifications on the functional hemispherectomy and involves removal of the temporal lobe mesial structures, exposure of the atrium via the circular sulcus, internal capsule transection under the central sulcus, intraventricular callosotomy, and frontobasal disconnection. The purpose of this article is to describe and illustrate in detail the anatomy and operative technique for periinsular hemispherotomy, as well as to discuss the nuances and issues involved with this procedure.
Leonardo Rangel-Castilla, Steven W. Hwang, George Al-Shamy, Andrew Jea, and Daniel J. Curry
Ashwin Viswanathan, Katherine Relyea, William E. Whitehead, Daniel J. Curry, Thomas G. Luerssen, and Andrew Jea
The authors describe a rare case of pneumothorax as a complication of thoracic pedicle screw placement in an 11-year-old girl undergoing posterior segmental instrumentation for a kyphotic deformity. Spontaneous pneumothorax after posterior fusion for adolescent idiopathic scoliosis has been reported in the orthopedic literature; however, to the best of the authors' knowledge, pneumothorax directly related to pedicle screw placement for spinal deformity has not been previously described. The authors discuss the anatomical and technical aspects leading to this complication and the lessons learned from it.
Roukoz B. Chamoun, William E. Whitehead, Daniel J. Curry, Thomas G. Luerssen, and Andrew Jea
The use of C-1 lateral mass screws provides an alternative to C1–2 transarticular screws in the pediatric population. However, the confined space of the local anatomy and unfamiliarity with the technique may make the placement of a C-1 lateral mass screw more challenging, especially in the juvenile or growing spine.
A CT morphometric analysis was performed in 76 pediatric atlases imaged at Texas Children's Hospital from October 1, 2007 until April 30, 2008. Critical measurements were determined for potential screw entry points, trajectories, and lengths, with the goal of replicating the operative technique described by Harms and Melcher for adult patients.
The mean height and width for screw entry on the posterior surface of the lateral mass were 2.6 and 8.5 mm, respectively. The mean medially angled screw trajectory from an idealized entry point on the lateral mass was 16° (range 4 to 27°). The mean maximal screw depth from this same ideal entry point was 20.3 mm. The overhang of the posterior arch averaged 6.3 mm (range 2.1–12.4 mm). The measurement between the left- and right-side lateral masses was significantly different for the maximum medially angled screw trajectory (p = 0.003) and the maximum inferiorly directed angle (p = 0.045). Those measurements in children < 8 years of age were statistically significant for the entry point height (p = 0.038) and maximum laterally angled screw trajectory (p = 0.025) compared with older children. The differences between boys and girls were statistically significant for the minimum screw length (p = 0.04) and the anterior lateral mass height (p < 0.001).
A significant variation in the morphological features of C-1 exists, especially between the left and right sides and in younger children. The differences between boys and girls are clinically insignificant. The critical measurement of whether the C-1 lateral mass in a child could accommodate a 3.5-mm-diameter screw is the width of the lateral mass and its proximity to the vertebral artery. Only 1 of 152 lateral masses studied would not have been able to accommodate a lateral mass screw. This study reemphasizes the importance of a preoperative CT scan of the upper cervical spine to assure safe and effective placement of the instrumentation at this level.
Virendra R. Desai, Jeffrey S. Raskin, Arvind Mohan, JoWinsyl Montojo, Valentina Briceño, Daniel J. Curry, and Sandi Lam
Intrathecal baclofen pumps are generally placed in children for the treatment of spasticity and dystonia. Use of implants in this pediatric population with comorbidities is reported to have a high risk of complications and infections. With the aim of reducing baclofen pump–related infections, a quality improvement project was instituted at the authors’ institution.
A workflow paradigm unique to baclofen pump implantation aimed at decreasing implant-related infections was implemented. All baclofen pump operations performed at the authors’ institution between August 2012 and June 2016 were reviewed. An infection prevention protocol was created and implemented in August 2014 based on a literature review and the consensus opinion of the pediatric neurosurgeons in the group. Compliance with the prevention bundle was tracked. Case outcomes before and after implementation of the protocol with a minimum of 3 months of follow-up were retrospectively reviewed. Univariate and multivariate analyses were performed to assess the association of the steps in the prevention bundle with infection and complication outcomes.
A total of 128 baclofen pump surgeries were performed (64 preprotocol and 64 postprotocol). The patient age range was 3 to 27 years. The overall compliance rate with the infection prevention bundle was 82%. The pre- and postimplementation infection rates were 12.5% and 6.3%, respectively (p = 0.225). The total pre- and postimplementation complication rates were 23.4% and 9.4%, respectively (p = 0.032). The absolute and relative risk reductions for infections were 6.3% (95% CI 3.8%–16.3%) and 50%, respectively; for complications, the absolute and relative risk reductions were 14.1% (95% CI 1.5%–26.7%) and 60%, respectively.
The total complication rate following intrathecal baclofen pump surgery was significantly lower after implementation of the quality improvement protocol. This study is an example of using checklist standardization to diminish special cause variability.
Helena Karlberg Hippard, Mehernoor Watcha, Amber J. Stocco, and Daniel Curry
Deep brain stimulation (DBS) has become accepted therapy for intractable dystonia and other movement disorders. The accurate placement of DBS electrodes into the globus pallidus internus is assisted by unimpaired microelectrode recordings (MERs). Many anesthetic and sedative drugs interfere with MERs, requiring the patient to be awake for target localization and neurological testing during the procedure. In this study, a novel anesthetic technique was investigated in pediatric DBS to preserve MERs.
In this paper, the authors describe a sedative/anesthetic technique using ketamine, remifentanil, dexmedetomidine, and nicardipine in 6 pediatric patients, in whom the avoidance of GABAergic stimulating drugs permitted excellent surgical conditions with no detrimental effects on intraoperative MERs. The quality of the MERs, and the frequency of its use in making electrode placement decisions, was reviewed.
All 6 patients had good-quality MERs. The data were of sufficient quality to make a total of 9 trajectory adjustments.
Microelectrode recordings in pediatric DBS can be preserved with a combination of dexmedetomidine and ketamine, remifentanil, and nicardipine. This preservation of MERs is particularly crucial in electrode placement in children.
Sudhakar Vadivelu, Matthew Willsey, Daniel J. Curry, and John W. McDonald III
Chronic neuropathic pain is a debilitating disease process associated with several medical disorders. Different from pain caused by inflammation, neuropathic pain is a diffuse pain disorder often found to be recalcitrant to the limited medical treatments available. Intractable nerve pain may benefit from other therapies capable of longer-lasting pain coverage or greater efficacy. A growing number of reports have emerged suggesting a role for stem cells as a cellular delivery source with neuroprotective agents opposing the effects of nerve damage. Here, the authors review the current experimental therapies examining the use of stem cells for the treatment of neuropathic pain disorders.
Joshua J. Chern, Akash J. Patel, Andrew Jea, Daniel J. Curry, and Youssef G. Comair
Focal cortical dysplasia (FCD) is an important cause of intractable epilepsy and is at times treatable by resection. The now widespread use of MR imaging and recent advancement of functional imaging have increased the number of patients undergoing surgical treatment for FCD. The objective of this review is to critically examine and to provide a summary of surgical series on FCD published since 2000.
Studies concerning surgery for FCD were identified from MEDLINE and references of selected articles and book chapters. Data from these included studies were summarized and analyzed to identify factors correlated with seizure outcome.
Sixteen studies were identified, and 469 patients met our selection criteria. Seizure-free outcome at 1-year postoperatively was achieved in 59.7% of the patients. Children and adults were equally likely to benefit from the surgery. Complete resection (OR 13.7, 95% CI 6.68–28.1; p < 0.0001) and temporal location (OR 2.15, 95% CI 1.26–3.69; p = 0.0073) were two positive prognostic indicators of seizure-free outcome. Utilization of invasive monitoring did not affect the chance of seizure remission, but firm conclusions could not be drawn because patients were not randomized.
The advancement of modern imaging has transformed the process of surgical candidate selection for partial epilepsy due to FCD. Patients from recent surgical series were more homogeneous in their clinical presentations and might represent FCD as an independent pathological entity. This likely explained the improved surgical outcome for this group of patients. These reports also documented the increased utilization of functional imaging, but their efficacy needs to be verified with further studies.
Daniel K. Fahim, Katherine Relyea, Vikram V. Nayar, Benjamin D. Fox, William E. Whitehead, Daniel J. Curry, Thomas G. Luerssen, and Andrew Jea
The authors describe the novel use of a table-mounted tubular retractor system (MetRx) originally designed for minimally invasive spine surgery, in the resection of an intraventricular arteriovenous malformation (AVM) in a 12-year-old child. The tubular retractor system may have several advantages over traditional Greenberg or Leyla retractors in selected intracranial procedures. In our case, the low-profile 4 × 22–mm tube and fixed table attachment offered excellent exposure of the trigone of the lateral ventricle where the choroidal AVM was located and from which it was completely resected. Immediate postoperative cerebral angiography confirmed that the entire AVM had been resected. The patient suffered no new neurological deficits as a result of the retractor system or the exposure that it afforded. Although the good clinical results of a single case cannot be directly compared with those obtained using other open techniques of intracranial surgery in larger series, microendoscopic surgery of the brain is an alternative to the other techniques and may be recommended as a time-saving, trauma-reducing procedure with the potential to improve postoperative outcomes.
Daniel K. Fahim, Keyne K. Johnson, William E. Whitehead, Daniel J. Curry, Thomas G. Luerssen, and Andrew Jea
Periosteal chondromas located in the spine are rare. The authors document an even more infrequent occurrence of a recurrent periosteal chondroma in the cervical spine of a 6-year-old boy. During the operation, a giant (> 7 cm in diameter) periosteal chondroma with involvement of the C-5 and C-6 vertebral bodies was resected. The vertebral column was reconstructed with anterior-posterior instrumentation. The pathological examination revealed that the tumor consisted of chondroid tissue with typical chondrocytes, confirming the diagnosis of periosteal chondroma.
Jonathan G. Thomas, Steven W. Hwang, Todd J. Blumberg, William E. Whitehead, Daniel J. Curry, Thomas G. Luerssen, and Andrew Jea
Over 85% of patients with myelomeningoceles require placement of a ventriculoperitoneal shunt for hydrocephalus, and between 25% and 85% of these patients develop scoliosis. Although most patients undergo repeated shunt series radiography to evaluate for device malfunction, scoliosis radiographs are less consistently obtained. The authors sought to determine if a correlation exists between these 2 radiographic techniques for a given patient, as shunt series are obtained with the patient supine, whereas scoliosis radiographs are acquired with the patient standing upright. The authors also endeavored to study if shunt series radiographs can reliably detect significant scoliosis.
The authors retrospectively reviewed a single institution's series of 593 patients with myelomeningoceles and identified all patients in whom a shunt series and scoliosis radiographs were obtained within a 6-month period. They reviewed the medical records and radiographs of these patients for demographic and radiographic parameters. They then applied a linear regression model and determined shunt series curve cutoffs to detect scoliotic curves greater than 20° and 50°.
Of the 593 patients identified, 116 did not have radiographs available for interpretation. Of the remaining 477 patients, 201 had radiographic evidence of scoliosis (42%), and 66 had both a shunt series and a scoliosis radiographs acquired within a 6-month interval. In 4 patients, both end vertebrae of the scoliotic curve could not be visualized on a single radiograph. The mean age of the remaining cohort was 10.6 ± 5.2 years and the mean curve magnitude was 58° ± 37°. Using identical end vertebrae, the mean shunt series curve magnitude was 49° ± 35°. The mean interval between both radiographs was 2.3 ± 3.3 months. The regression model showed a strong linear association between shunt series and scoliosis series curves. A curve greater than 19° on shunt series radiographs would detect significant curves of greater than 20° on scoliosis series with 91% sensitivity and 78% specificity. A shunt series curve greater than 37° had 100% sensitivity and 93% specificity in identifying significant scoliotic curves greater than 50°.
Although shunt series radiographs may not precisely depict scoliotic curve magnitude because the impact of gravity is negated, they may be useful in helping to confirm clinical suspicion of scoliosis. The authors' results suggest a strong correlation between both types of radiographs.