Daniel E. Couture

Outcome analysis of our first 75 spring-assisted surgeries for scaphocephaly.

Background: Spring-assisted surgery (SAS) has demonstrated promising results for the treatment of sagittal craniosynostosis. The purpose of this study was to assess the outcomes of the first 75 cases compared with a prospectively collected group of patients treated with cranial expansion (cranial vault remodeling [CVR]). Methods: Seventy-five children with scaphocephaly have completed this institutional review board-approved study. Patients underwent cranial surgery with removal of a 1-cm strip of sagittal suture and insertion of a mean of 2 spring distractors. Clinical outcome assessment included analysis of changes in cephalic index, shape, and volume on three-dimensional laser scans for both the SAS and the CVR treatments. Perioperative variables for both techniques were also compared. Results: All patients successfully underwent SAS without significant complications with a mean follow-up of 46 months. Perioperative variables including odds ratio, time, blood loss, transfusion requirements, intensive care unit and hospital stay lengths, and hospital costs differed significantly in favor of SAS. The mean cephalic index improved from 69 preoperatively to 75.4 after SAS, comparable with the change from 66 to 72.5 for CVR. This correction was maintained at 3- and 5-year follow-ups. Anterior frontal bossing was corrected on three-dimensional scan volume measurements. Conclusions: Spring-assisted surgery is a safe, effective, minimally invasive treatment of scaphocephaly. It combines the low morbidity and the operative time of a strip craniectomy with dynamic reshaping techniques while the implanted spring gradually distracts the skull, improving head shape. Our 7 years of experience has shown that SAS effectively corrected cranial shape including frontal bossing with maintained results over time.

Subcortical connections of normotopic and heterotopic neurons in sensory and motor cortices of the tish mutant rat

Orthograde and retrograde tracers were used to examine subcortical connections of neurons in the neurological mutant tish rat. This animal exhibits bilateral heterotopia similar to those observed in epileptic humans with subcortical band heterotopia. Terminal varicosities were labeled in the striatum, thalamus, brainstem, and spinal cord following injections of the anterograde tracer biotinylated dextran amine (BDA) into the heterotopic cortex. The general topography of corticothalamic projections was evaluated by injecting the retrograde tracer Fluoro‐Gold (FG) into ventral thalamic nuclei. Retrograde labeling of small‐to‐medium sized neurons was observed in layer VI of topographically restricted portions of the normotopic cortex. Similar appearing cells were labeled in the neighboring portions of the underlying heterotopia; however, these neurons did not display characteristic lamination or radial orientation. Thalamocortical terminals labeled by injecting BDA into the ventroposterolateral nucleus (VPL) were observed primarily in layer IV of the medial aspect of the normotopic somatosensory cortex. In contrast, a radial column of terminals was present in the underlying heterotopia. Typical barrel labeling was found in the lateral aspect of the normotopic somatosensory cortex after injecting the ventroposteromedial nucleus (VPM), whereas more diffuse patches of labeling were observed in the underlying heterotopia.

Effects of antibiotic-impregnated external ventricular drains on bacterial culture results: an in vitro analysis

OBJECT Treatment of ventriculoperitoneal shunt infections frequently requires placement of an external ventricular drain (EVD). Surveillance specimens obtained from antibiotic-impregnated (AI) EVDs may be less likely to demonstrate bacterial growth, potentially resulting in undertreatment of an infection. The purpose of this study was to assess whether AI EVDs had any significant effect on bacterial culture results compared with nonantibiotic-impregnated (NAI) EVDs. METHODS In vitro assays were performed using AI EVDs containing minocycline and rifampin (VentriClear II, Medtronic) and NAI EVD controls (Bioglide, Medtronic). The presence of antibiotics was evaluated via capillary electrophoresis of sterile saline drawn from AI and NAI EVDs after predefined incubation intervals. Antimicrobial activity was assessed by evaluating zones of inhibition created by the catheter aspirates on plates inoculated with a quality control strain of Staphylococcus epidermidis (American Type Culture Collection strain 12228). To determine the effects of cultures drawn through AI compared with NAI EVDs, the quality control strain was then incubated within 4 new AI and 4 new NAI EVDs for predefined intervals before being plated on culture media. Spread and streak plate culture results from each type of catheter were compared at each time interval. RESULTS Capillary electrophoresis showed that more minocycline than rifampin was eluted from the AI EVDs. Sterile saline samples incubated within the AI EVDs demonstrated zones of growth inhibition when placed on plates of S. epidermidis at all time intervals tested. No zones of inhibition were noted on NAI EVD control plates. When a standardized inoculum of S. epidermidis was drawn through AI and NAI EVDs, antimicrobial effects were observed after incubation in the AI EVD group only. Colony counting demonstrated that significantly fewer colonies resulted from samples drawn through AI compared with NAI EVDs at the multiple time intervals. Similarly, streak plating yielded a statistically significant number of false-negative results from AI compared with NAI EVDs at 2 time intervals. CONCLUSIONS The findings in the current study indicate that the risk of a false-negative culture result may be increased when a CSF sample is drawn through an AI catheter. In the management of a known shunt infection, a false-negative result from an EVD culture specimen may lead to an inappropriately short duration of antibiotic therapy. These data have significant clinical implications, particularly given the widespread use of AI drains and the current high rates of shunt reinfection after EVD use worldwide.

Occipitocervical instrumentation in the pediatric population using a custom loop construct: initial results and long-term follow-up experience

OBJECT Rigid occipitocervical instrumentation for craniovertebral instability is gaining widespread acceptance for use in pediatric patients; however, most of the instrumentation has been modified from adult-sized hardware. The Wasatch loop system (formerly the Avery-Brockmeyer-Thiokol loop system) is a rigid occipitocervical fixation device designed specifically for use in children. It affixes to the occiput and incorporates either C1-2 transarticular screws or C-2 pars screws. It is preformed and is available in a variety of sizes. The authors describe their clinical experience and long-term follow-up experience with the first 22 patients. METHODS An institutional review board-approved retrospective review of medical records and radiographs was performed for patients who underwent occipitocervical fusion with the Wasatch loop. The mean patient age was 4.9 years (1.2-13 years), and the overall mean follow-up was 4 years (1.5-6.5 years). Six patients had posttraumatic instability, and 16 patients had congenital instability. RESULTS Twelve patients underwent placement of bilateral C1-2 transarticular screws, 6 patients had placement of a combination of C1-2 transarticular and C-2 pars screws, and 4 patients had placement of bilateral C-2 pars screws. One patient required a halo orthosis; the others were treated postoperatively with a hard cervical collar. All patients had radiographic evidence of solid occipitocervical arthrodesis on last follow-up examination. CONCLUSIONS The Wasatch loop system is a novel internal fixation device for children who have posttraumatic or congenital occipitocervical instability. Successful arthrodesis was achieved in all patients with minimal use of halo orthoses.

Carotid endarterectomy: can we select surgical candidates at high risk for stroke and low risk for perioperative complications?

DESPITE EVIDENCE OF the efficacy of carotid endarterectomy from the large randomized multicenter trials completed in the 1990s, the physician who treats patients with carotid artery stenosis still is faced with a difficult management decision. More recently, subgroup analyses have been conducted of asymptomatic and symptomatic patients enrolled in these trials to identify clinical and radiological factors that increase the rates of morbidity and mortality associated with surgery, as well as those that increase the risk of stroke without surgery. Knowledge of these factors is important to recommend the best course of action for the individual patient. In this article, we summarize the conclusions of some of the subgroup analyses from the major carotid endarterectomy trials.

Spring-assisted surgery-a surgeon's manual for the manufacture and utilization of springs in craniofacial surgery.

Background and Purpose: Spring-assisted surgery has been used for the treatment of craniofacial deformities since its 1997 inception in Sweden by Dr Lauritzen (Scand J Plast Reconstr Surg Hand Surg 1998;32:331-338). Initial applications have focused on the treatment of patients with single-suture craniosynostosis. Recently, indications and applications have expanded to include patients with syndromic craniosynostosis, multiple-suture synostosis, and midface hypoplasia. The advancement of spring-assisted surgery in this country has been hindered by the need for patient-specific spring fabrication because few surgeons understand how to make the springs for each application. We will review our spring design and treatment algorithms to facilitate wider use of this innovative treatment modality. Methods: This is a retrospective institutional review board-approved analysis of the spring design for our first 90 cases of spring-assisted surgery used to treat sagittal synostosis at the North Carolina Center for Cleft and Craniofacial Deformities. Outcome analysis was done to generate a treatment algorithm based on diagnosis, patient age, spring design, number of springs, spring force and expansion, and clinical outcome. Results: Ninety children with sagittal craniosynostosis (64 males, 26 females) were treated during an 8-year period (2001-2009) with spring-assisted surgery. Mean age at treatment was 4.4 months and mean age at spring removal was 8.8 months. Mean number of springs used was 2 (range, 1-3). Mean spring force used in sagittal synostosis was 5.5-9.5 (range) for the anterior spring and 5.5-9.5 (range) for the posterior spring with a mean posttreatment expansion of 6.65 cm. Analysis of the results shows that spring force and expansion required for optimal correction is dependent on the age at surgery, type of the deformity, and severity of the deformity. Specifically, the younger the child, the weaker the spring needed for surgical correction. General principles for spring application for scaphocephaly include (1) the longer the anterior posterior dimension of the skull deformity, the more likely a third spring is necessary; (2) the narrower the posterior occiput, the stronger the posterior spring required; and (3) if a postcoronal band is seen in the calvarium, a stronger anterior spring is needed. Conclusions: Long-term experience with spring-assisted surgery has facilitated the development of standardized, reproducible techniques allowing spring design modifications to optimize clinical outcome.

Long-term growth and alignment after occipitocervical and atlantoaxial fusion with rigid internal fixation in young children

OBJECT The long-term consequences of atlantoaxial (AA) and occipitocervical (OC) fusion and instrumentation in young children are unknown. Anecdotal reports have raised concerns regarding altered growth and alignment of the cervical spine after surgical intervention. The purpose of this study was to determine the long-term effects of these surgeries on the growth and alignment of the maturing spine. METHODS A multiinstitutional retrospective chart review was conducted for patients less than or equal to 6 years of age who underwent OC or AA fusion with rigid instrumentation at 9 participating centers. All patients had at least 3 years of clinical and radiographic follow-up data and radiographically confirmed fusion. Preoperative, immediate postoperative, and most recent follow-up radiographs and/or CT scans were evaluated to assess changes in spinal growth and alignment. RESULTS Forty children (9 who underwent AA fusion and 31 who underwent OC fusion) were included in the study (mean follow-up duration 56 months). The mean vertical growth over the fused levels in the AA fusion patients represented 30% of the growth of the cervical spine (range 10%-50%). Three different vertical growth patterns of the fusion construct developed among the 31 OC fusion patients during the follow-up period: 1) 16 patients had substantial growth (13%-46% of the total growth of the cervical spine); 2) 9 patients had no meaningful growth; and 3) 6 patients, most of whom presented with a distracted atlantooccipital dislocation, had a decrease in the height of the fused levels (range 7-23 mm). Regarding spinal alignment, 85% (34/40) of the patients had good alignment at follow-up, with straight or mildly lordotic cervical curvatures. In 1 AA fusion patient (11%) and 5 OC fusion patients (16%), we observed new hyperlordosis (range 43°-62°). There were no cases of new kyphosis or swan-neck deformity, evidence of subaxial instability, or unintended subaxial fusion. No preoperative predictors of these growth patterns or alignment were evident. CONCLUSIONS These results demonstrate that most young children undergoing AA and OC fusion with rigid internal fixation continue to have good cervical alignment and continued growth within the fused levels during a prolonged follow-up period. However, some variability in vertical growth and alignment exists, highlighting the need to continue close long-term follow-up.

Evaluating the safety and efficacy of tranexamic acid administration in pediatric cranial vault reconstruction.

BackgroundBlood loss is the leading cause of mortality after major craniofacial surgery. Autologous blood donation, short-term normovolemic hemodilution, and intraoperative blood salvage have shown low efficacy in decreasing transfusions. Tranexamic acid (TXA) is a synthetic antifibrinolytic drug that competitively decreases the conversion of plasminogen to plasmin, thereby suppressing fibrinolysis. The purpose of this study was to investigate the impact that TXA administration has on intraoperative blood loss and blood product transfusion in pediatric patients undergoing cranial vault reconstruction. MethodsAn Internal Review Board-approved retrospective study was conducted on a consecutive series of pediatric patients undergoing cranial vault reconstruction from January 2009 to June 2012. Seventeen consecutive patients who received TXA at the time of cranial vault reconstruction were compared with 20 patients who did not receive TXA. Criteria for blood product transfusion were identical for both groups. Outcomes including perioperative blood loss, volume of blood transfused, and adverse effects were analyzed. ResultsThe TXA group had a significantly lower perioperative blood loss (9.4 versus 21.1 mL/kg, P < 0.0001) and lower volume of perioperative mean blood product transfusion (12.8 versus 31.3 mL/kg, P < 0.0001) compared with the non-TXA group. There was no significant difference in demographic data, infection rate, change in preoperative to postoperative hematocrit, duration of surgery, or complication rates between the TXA and non-TXA groups. No drug-related adverse effects were identified in patients who received TXA. ConclusionsThe use of TXA in pediatric cranial vault reconstruction significantly reduces perioperative blood loss and blood product transfusion requirements. The TXA administration is safe and may improve patient outcomes by decreasing the likelihood of adverse effects related to blood product transfusion.

Increased incidence of metopic suture abnormalities in children with positional plagiocephaly.

Metopic craniosynostosis has traditionally been reported to be the third most common form of single-suture synostosis. The purposes of this article were to analyze the relationship between metopic craniosynostosis and positional plagiocephaly and to define more clearly the differences between the changes seen with true suture fusion compared with metopic abnormalities secondary to positional changes. This is an institutional review board-approved retrospective review of three-dimensional computed tomographic scans for abnormalities of the metopic suture in all children treated at our institution for positional plagiocephaly between 1997 and 2007. We also independently reviewed the images of all patients treated for metopic synostosis for evidence of positional plagiocephaly during the same period. Among the positional plagiocephaly group, 39% were noted to have some form of metopic suture abnormality. Of the children treated for metopic craniosynostosis, a much smaller percentage also was noted to have evidence of positional plagiocephaly. Between 1997 and 2007, we treated 93 patients (50%) for sagittal synostosis, 41 patients (22%) for unicoronal, 41 patients (22%) for metopic, 4 patients (2%) for lamdoid, and 7 patients (4%) with multiple-suture involvement. This study demonstrates an increasing trend toward metopic suture abnormalities during the past 10 years, which corresponds to the same time interval of an increased incidence of positional abnormalities. It is postulated that some of these abnormalities are related to deformational forces resulting from posterior pressure. Altered mechanical forces from supine infant positioning may be associated with early metopic suture ridging and dysmorphology distinct from true craniosynostosis.

Laser Interstitial Thermal Therapy for Mesial Temporal Lobe Epilepsy

Approximately one-third of patients with epilepsy do not achieve adequate seizure control through medical management alone. Mesial temporal lobe epilepsy (MTLE) is one of the most common forms of medically refractory epilepsy referred for surgical management. Stereotactic laser amygdalohippocampotomy using magnetic resonance-guided laser interstitial thermal therapy (MRg-LITT) is an important emerging therapy for MTLE. Initial published reports support MRg-LITT as a less invasive surgical option with a shorter hospital stay and fewer neurocognitive side effects compared with craniotomy for anterior temporal lobectomy with amygdalohippocampectomy and selective amygdalohippocampectomy. We provide a historical overview of laser interstitial thermal therapy development and the technological advancements that led to the currently available commercial systems. Current applications of MRg-LITT for MTLE, reported outcomes, and technical issues of the surgical procedure are reviewed. Although initial reports indicate that stereotactic laser amygdalohippocampotomy may be a safe and effective therapy for medically refractory MTLE, further research is required to establish its long-term effectiveness and its cost/benefit profile. ABBREVIATIONS ATLAH, anterior temporal lobectomy with amygdalohippocampectomyLITT, laser interstitial thermal therapyMRg-LITT, magnetic resonance-guided laser interstitial thermal therapyMTLE, mesial temporal lobe epilepsySAH, selective amygdalohippocampectomySLAH, stereotactic laser amygdalohippocampotomy.