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Short lever arm, bipedicular handlebar construct for correction of acute angular kyphosis in spondylodiscitis-induced kyphotic deformity: illustrative case

Meng Huang, Iahn Cajigas, and Steven Vanni

BACKGROUND

Pyogenic spondylodiscitis diminishes spinal structural integrity via disruption of the anterior and middle column, sometimes further compounded by iatrogenic violation of the posterior tension band during initial posterior decompressive surgeries. Although medical management is typically sufficient, refractory infection or progressive deformity may require aggressive debridement and reconstructive arthrodesis. Although anterior debridement plus reconstruction with posterior stabilization is an effective treatment option, existing techniques have limited efficacy for correcting focal deformity, leaving patients at risk for long-term sagittal imbalance, pain, and disability.

OBSERVATIONS

The authors present a case of chronic lumbar pyogenic spondylodiscitis in a patient in whom initial surgical debridement failed and pronounced angular kyphosis and intractable low back pain developed. A novel bipedicular handlebar construct was used to achieve angular correction of the kyphosis through simultaneous anterior interbody grafting and posterior instrumentation with the patient in the lateral position.

LESSONS

Leveraging both pedicle screws at the same level to transmit controlled corrective distraction forces through the segment allows for kyphosis correction without relying on long posterior constructs for cantilever reduction. Simultaneous anterior reconstruction with a posterior short lever arm, bipedicular handlebar construct is an effective technique for achieving high angular correction during circumferential reconstructive approaches to postinfectious focal kyphotic deformities.

Free access

Cerebellar deep brain stimulation for the treatment of movement disorders in cerebral palsy

Iahn Cajigas, Melanie A. Morrison, Marta San Luciano, and Philip A. Starr

OBJECTIVE

Cerebral palsy (CP) represents the most common childhood physical disability that encompasses disorders of movement and posture attributed to nonprogressive disturbances that occurred in the developmental fetal or infant brain. Dyskinetic CP (DCP), the second most common type of CP after spastic forms, refers to a subset of patients in whom dystonia and choreoathetosis are the predominant motor manifestations. Most children with CP have abnormal brain MRI studies indicative of cortical and deep gray matter damage consistent with hypoxic ischemic encephalopathy, which may preclude or suggest decreased efficacy of standard deep brain stimulation (DBS) targets. The cerebellum has been posited as an attractive target for treatment of DCP because it is frequently spared from hypoxic ischemic damage and has shown promise in alleviating patient symptoms both in early work in the 1970s and in more recent case series with DBS.

METHODS

The authors performed bilateral cerebellar DBS implantation, targeting the dentate nucleus (DN) and cerebellar outflow pathway, in 3 patients with DCP. Leads were connected to a pulse generator that senses local field potentials during chronic continuous DBS. The authors report their surgical methods, examples of chronic cerebellar local field potential recordings, and preliminary clinical outcomes. Motor outcomes were assessed using the Burke-Fahn-Marsden Dystonia Rating Scale.

RESULTS

Three patients 14–22 years old with DCP and MRI evidence of structural damage to the basal ganglia were offered cerebellar stimulation targeting the DN. All patients tolerated the procedure well and demonstrated improvement in subjective motor function as well as objective improvement in the Burke-Fahn-Marsden Dystonia Rating Scale movement subscale, although the range of responses was variable (19%–40%). Patients experienced subjective improvement in motor function including ease of hand movements and coordination, gait, head control, speech, decreased overflow, and diminished muscle tightness.

CONCLUSIONS

DBS of the dentate nuclei in patients with DCP appears to be safe and shows preliminary evidence of clinical benefit. New chronic sensing technology may allow for determination of in vivo mechanisms of network disruption in DCP and allow for further understanding of the effects of neuromodulation on brain physiology. Larger studies with long-term follow up will be required to further elucidate the clinical benefits of this therapy. This report addresses a gap in the literature regarding the technical approach to image-based stereotactic targeting and chronic neural recording in the DN.

Free access

Effects of an external ventricular drain alert protocol on venticulostomy placement time in the emergency department

Henry Chang, Michael A. Silva, Alexander Giner, Selina Ancheta, José G. Romano, Ricardo Komotar, and Iahn Cajigas

OBJECTIVE

Timely ventriculostomy placement is critical in the management of neurosurgical emergencies. Prompt external ventricular drain (EVD) placement has been shown to improve long-term patient outcomes and decrease the length of ICU and hospital stays. Successful and efficient EVD placement requires seamless coordination among multiple healthcare teams. In this study, the authors sought to identify factors favoring delayed ventriculostomy via a quality improvement initiative and to implement changes to expedite EVD placement.

METHODS

Through process mapping, root cause analysis, and interviews with staff, the authors identified the lack of a standardized mechanism for alerting necessary healthcare teams as a major contributor to delays in EVD placement. In December 2019, an EVD alert system was developed to automatically initiate an EVD placement protocol and to alert the neurosurgery department, pharmacy, core laboratory, and nursing staff to prepare for EVD placement. The time to EVD placement was tracked prospectively using time stamps in the electronic medical record.

RESULTS

A total of 20 patients who underwent EVD placement between December 2019 and April 2021, during the EVD alert protocol initiation, and 18 preprotocol control patients (January 2018 to December 2019) met study inclusion criteria and were included in the analysis. The mean time to EVD placement in the control group was 71.88 minutes compared with 50.3 minutes in the EVD alert group (two-tailed t-test, p = 0.025). The median time to EVD placement was 64 minutes in the control group compared with 52 minutes in the EVD alert group (rank-sum test, p = 0.0184). All patients from each cohort exhibited behavior typical of stable processes, with no violation of Shewhart rules and no special cause variations on statistical process control charts.

CONCLUSIONS

A quality improvement framework helped identify sources of delays to EVD placement in the emergency department. An automated EVD alert system was a simple intervention that significantly reduced the time to EVD placement in the emergency department and can be easily implemented at other institutions to improve patient care.

Free access

Machine learning to predict passenger mortality and hospital length of stay following motor vehicle collision

John Paul G. Kolcun, Brian Covello, Joanna E. Gernsback, Iahn Cajigas, and Jonathan R. Jagid

OBJECTIVE

Motor vehicle collisions (MVCs) account for 1.35 million deaths and cost $518 billion US dollars each year worldwide, disproportionately affecting young patients and low-income nations. The ability to successfully anticipate clinical outcomes will help physicians form effective management strategies and counsel families with greater accuracy. The authors aimed to train several classifiers, including a neural network model, to accurately predict MVC outcomes.

METHODS

A prospectively maintained database at a single institution’s level I trauma center was queried to identify all patients involved in MVCs over a 20-year period, generating a final study sample of 16,287 patients from 1998 to 2017. Patients were categorized by in-hospital mortality (during admission) and length of stay (LOS), if admitted. All models included age (years), Glasgow Coma Scale (GCS) score, and Injury Severity Score (ISS). The in-hospital mortality and hospital LOS models further included time to admission.

RESULTS

After comparing a variety of machine learning classifiers, a neural network most effectively predicted the target features. In isolated testing phases, the neural network models returned reliable, highly accurate predictions: the in-hospital mortality model performed with 92% sensitivity, 90% specificity, and a 0.98 area under the receiver operating characteristic curve (AUROC), and the LOS model performed with 2.23 days mean absolute error after optimization.

CONCLUSIONS

The neural network models in this study predicted mortality and hospital LOS with high accuracy from the relatively few clinical variables available in real time. Multicenter prospective validation is ultimately required to assess the generalizability of these findings. These next steps are currently in preparation.

Free access

One-donor, two-recipient extracranial-intracranial bypass series for moyamoya and cerebral occlusive disease: rationale, clinical and angiographic outcomes, and intraoperative blood flow analysis

Nickalus R. Khan, Victor M. Lu, Turki Elarjani, Michael A. Silva, Aria M. Jamshidi, Iahn Cajigas, and Jacques J. Morcos

OBJECTIVE

Cerebral extracranial-intracranial (EC-IC) direct bypass is a commonly used procedure for ischemic vasculopathy. A previously described variation of this technique is to utilize one donor artery to supply two recipient arteries, which the authors designate as 1D2R. The purpose of this study is to present a single surgeon’s series of 1D2R direct bypasses for moyamoya and ischemia using detailed clinical, angiographic, and intraoperative blood flow measurement data. To the authors’ knowledge, this is the largest series reported to date.

METHODS

Hospital, office, and radiographic imaging records for all patients who underwent cerebral revascularization using a 1D2R bypass by the senior author were reviewed. The patients’ demographic information, clinical presentation, associated medical conditions, intraoperative information, and postoperative course were obtained from reviewing the medical records.

RESULTS

A total of 21 1D2R bypasses were performed in 19 patients during the study period. Immediate bypass patency was 100% and was 90% on delayed follow-up. The mean initial cut flow index (CFI(i)) was 0.64 ± 0.33 prior to the second anastomosis and the mean final value (CFI(f)) was 0.94 ± 0.38 after the second anastomosis (p < 0.001). The overall bypass flow increased on average by 50% (mean 17.9 ml/min, range −10 to 40 ml/min) with the addition of the second anastomosis. There was no significant difference in the overall flow measurements when the end-to-side anastomosis or side-to-side anastomosis was performed first. There was a statistically significant difference in the proportion of patients with a modified Rankin Scale (mRS) score of 0 or 1 postoperatively compared to preoperatively (p < 0.01). Through the application of Poiseuille’s law, the authors analyzed flow dynamics, deduced the component vascular resistances based on an analogy to electrical circuits and Ohm’s law, and introduced the new concepts of “second anastomosis relative augmentation” and “second anastomosis sink index” in the evaluation of 1D2R bypasses.

CONCLUSIONS

The application of the 1D2R technique in a series of 19 consecutive patients undergoing direct EC-IC bypass for flow augmentation demonstrated high patency rates, statistically significantly higher CFIs compared to 1D1R, and improved mRS scores at last clinical follow-up. Additionally, the technique allows a shorter dissection time and preserves blood flow to the scalp. The routine utilization of intraoperative volumetric flow measurements in such surgeries allows a deeper understanding of the hemodynamic impact on individual patients.

Restricted access

Letter to the Editor. Cerebellar DBS in cerebral palsy

Vengalathur Ganesan Ramesh

Free access

Endoscopic third ventriculostomy with choroid plexus cauterization for the treatment of infantile hydrocephalus in Haiti

Ashish H. Shah, Yudy LaFortune, George M. Ibrahim, Iahn Cajigas, Michael Ragheb, Stephanie H. Chen, Ernest J. Barthélemy, Ariel Henry, and John Ragheb

OBJECTIVE

Untreated hydrocephalus poses a significant health risk to children in the developing world. In response to this risk, global neurosurgical efforts have increasingly focused on endoscopic third ventriculostomy with choroid plexus cauterization (ETV/CPC) in the management of infantile hydrocephalus in low- and middle-income countries (LMICs). Here, the authors report their experience with ETV/CPC at the Hospital Bernard-Mevs/Project Medishare (HBMPM) in Port-au-Prince, Haiti.

METHODS

The authors conducted a retrospective review of a series of consecutive children who had undergone ETV/CPC for hydrocephalus over a 1-year period at HBMPM. The primary outcome of interest was time to ETV/CPC failure. Univariate and multivariate analyses using a Cox proportional hazards regression were performed to identify preoperative factors that were associated with outcomes.

RESULTS

Of the 82 children who underwent ETV/CPC, 52.2% remained shunt free at the last follow-up (mean 6.4 months). On univariate analysis, the ETV success score (ETVSS; p = 0.002), success of the attempted ETV (p = 0.018), and bilateral CPC (p = 0.045) were associated with shunt freedom. In the multivariate models, a lower ETVSS was independently associated with a poor outcome (HR 0.072, 95% CI 0.016–0.32, p < 0.001). Two children (2.4%) died of postoperative seizures.

CONCLUSIONS

As in other LMICs, ETV/CPC is an effective treatment for hydrocephalus in children in Haiti, with a low but significant risk profile. Larger multinational prospective databases may further elucidate the ideal candidate for ETV/CPC in resource-poor settings.

Free access

Modern intracranial electroencephalography for epilepsy localization with combined subdural grid and depth electrodes with low and improved hemorrhagic complication rates

Anthony T. Lee, Noah M. Nichols, Benjamin A. Speidel, Joline M. Fan, Iahn Cajigas, Robert C. Knowlton, and Edward F. Chang

OBJECTIVE

Recent trends have moved from subdural grid electrocorticography (ECoG) recordings toward stereo-electroencephalography (SEEG) depth electrodes for intracranial localization of seizures, in part because of perceived morbidity from subdural grid and strip electrodes. For invasive epilepsy monitoring, the authors describe the outcomes of a hybrid approach, whereby patients receive a combination of subdural grids, strips, and frameless stereotactic depth electrode implantations through a craniotomy. Evolution of surgical techniques was employed to reduce complications. In this study, the authors review the surgical hemorrhage and functional outcomes of this hybrid approach.

METHODS

A retrospective review was performed of consecutive patients who underwent hybrid implantation from July 2012 to May 2022 at an academic epilepsy center by a single surgeon. Outcomes included hemorrhagic and nonhemorrhagic complications, neurological deficits, length of monitoring, and number of electrodes.

RESULTS

A total of 137 consecutive procedures were performed; 113 procedures included both subdural and depth electrodes. The number of depth electrodes and electrode contacts did not increase the risk of hemorrhage. A mean of 1.9 ± 0.8 grid, 4.9 ± 2.1 strip, and 3.0 ± 1.9 depth electrodes were implanted, for a mean of 125.1 ± 32 electrode contacts per patient. The overall incidence of hematomas over the study period was 5.1% (7 patients) and decreased significantly with experience and the introduction of new surgical techniques. The incidence of hematomas in the last 4 years of the study period was 0% (55 patients). Symptomatic hematomas were all delayed and extra-axial. These patients required surgical evacuation, and there were no cases of hematoma recurrence. All neurological deficits related to hematomas were temporary and were resolved at hospital discharge. There were 2 nonhemorrhagic complications. The mean duration of monitoring was 7.3 ± 3.2 days. Seizures were localized in 95% of patients, with 77% of patients eventually undergoing resection and 17% undergoing responsive neurostimulation device implantation.

CONCLUSIONS

In the authors’ institutional experience, craniotomy-based subdural and depth electrode implantation was associated with low hemorrhage rates and no permanent morbidity. The rate of hemorrhage can be nearly eliminated with surgical experience and specific techniques. The decision to use subdural electrodes or SEEG should be tailored to the patient’s unique pathology and surgeon experience.

Restricted access

Oral Presentations 2016 AANS Annual Scientific Meeting Chicago, IL • April 30–May 4, 2016

Published online April 1, 2016; DOI: 10.3171/2016.4.JNS.AANS2016abstracts