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.
Sudhakar Vadivelu, Matthew Willsey, Daniel J. Curry and John W. McDonald III
Leonardo Rangel-Castilla, Steven W. Hwang, George Al-Shamy, Andrew Jea and Daniel J. Curry
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.
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.
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.
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.
Pamela S. Jones, Daniel P. Cahill, Priscilla K. Brastianos, Keith T. Flaherty and William T. Curry
In patients with large or symptomatic brain lesions from metastatic melanoma, the value of resection of metastases to facilitate administration of systemic ipilimumab therapy has not yet been described. The authors undertook this study to investigate whether craniotomy creates the opportunity for patients to receive and benefit from ipilimumab who would otherwise succumb to brain metastasis prior to the onset of regression.
All patients with metastatic melanoma who received ipilimumab and underwent craniotomy for metastasis resection between 2008 and 2014 at the Massachusetts General Hospital were identified through retrospective chart review. The final analysis included cases involving patients who underwent craniotomy within 3 months prior to initiation of therapy or up to 6 months after cessation of ipilimumab administration.
Twelve patients met the inclusion criteria based on timing of therapy (median age 59.2). The median number of metastases at the time of craniotomy was 2. The median number of ipilimumab doses received was 4. Eleven of 12 courses of ipilimumab were stopped for disease progression, and 1 was stopped for treatment-induced colitis. Eight of 12 patients had improvement in their performance status following craniotomy. Of the 6 patients requiring corticosteroids prior to craniotomy, 3 tolerated corticosteroid dose reduction after surgery. Ten of 12 patients had died by the time of data collection, with 1 patient lost to follow-up. The median survival after the start of ipilimumab treatment was 7 months.
In this series, patients who underwent resection of brain metastases in temporal proximity to receiving ipilimumab had qualitatively improved performance status following surgery in most cases. Surgery facilitated corticosteroid reduction in select patients. Larger analyses are required to better understand possible synergies between craniotomy for melanoma metastases and ipilimumab treatment.
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.
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.
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.
Pamela S. Jones, Gavin P. Dunn, Fred G. Barker II, William T. Curry, Fred H. Hochberg and Daniel P. Cahill
The authors' goal was to review the current understanding of the underlying molecular and genetic mechanisms involved in low-grade glioma development and how these mechanisms can be targets for detection and treatment of the disease and its recurrence.
On October 4, 2012, the authors convened a meeting of researchers and clinicians across a variety of pertinent medical specialties to review the state of current knowledge on molecular genetic mechanisms of low-grade gliomas and to identify areas for further research and drug development.
The meeting consisted of 3 scientific sessions ranging from neuropathology of IDH1 mutations; CIC, ATRX, and FUBP1 mutations in oligodendrogliomas and astrocytomas; and IDH1 mutations as therapeutic targets. Sessions consisted of a total of 10 talks by international leaders in low-grade glioma research, mutant IDH1 biology and its application in glioma research, and treatment.
The recent discovery of recurrent gene mutations in low-grade glioma has increased the understanding of the molecular mechanisms involved in a host of biological activities related to low-grade gliomas. Understanding the role these genetic alterations play in brain cancer initiation and progression will help lead to the development of novel treatment modalities than can be personalized to each patient, thereby helping transform this now often-fatal malignancy into a chronic or even curable disease.