The influence of surgical operative experience on the duration of first ventriculoperitoneal shunt function and infection.

The relationship of surgeon experience, measured by operative volume, to the outcomes of ventricular shunt treatment of hydrocephalus in children is not clear. This paper explores this relationship based on first ventriculoperitoneal shunts (VPS) implanted in English-speaking Canada during the period from April 1989 to March 2001. Three thousand seven hundred and ninety-four first VPS insertions, performed by 254 surgeons, were reviewed. Surgical experience was represented by the number of shunt operations performed during the study period by each surgeon prior to the date of the operation. The 6-month shunt failure risk for less experienced surgeons was 38%, compared to 31% for more experienced surgeons. This difference decreased to 4% at 60 months and 3% at 120 months (p = 0.001). The infection rate for initial shunt insertions was 7% for patients treated by more experienced surgeons and 9.4% for those treated by less experienced surgeons (p = 0.006). A relationship between surgeon experience and shunt outcome that appears to be based on the operative experience that a surgeon brings to a procedure is in keeping with clinical experience. This observation has implications for public policy, service planning and surgical mentorship during the earlier years of a surgeon's career.

Ventricular shunting for hydrocephalus in children: patients, procedures, surgeons and institutions in English Canada, 1989-2001.

INTRODUCTION AND PURPOSE: Ventricular shunting remains the principle and most generally applicable method to treat hydrocephalus in children. This paper describes the demographics of this treatment in English Canada during the period of 1989 to March 2001. METHODS: Hospital discharge records were obtained for patients less than 18 years who had a shunt inserted or revised. A database was constructed relating patients and procedures to hospital discharges based on scrambled patient identifiers, year of birth, sex, postal code and diagnoses. OBSERVATIONS: 5,947 patients underwent ventricular shunting procedures for hydrocephalus in this period. 261 surgeons working in 73 institutions provided 12,106 interventions (Shunt insertions: ventriculoperitoneal--5009, ventriculoatrial--119, ventriculopleural--28. Revisions: 6,950). Infection was deemed to have occurred in 1,059 procedures. Over the study period, the median number of procedures performed per surgeon per year was 2, with 75 % of surgeons performing 5 or fewer procedures in children per year. Although many surgeons operated on children throughout the thirteen years of the study, many did not acquire substantive cumulative experience. Overall infection rate was 8.6 %. Surgeon infection rates were greater than or equal to 20 % during the first four years of practice and thereafter they fell to and remained in the 10 % range. The mean shunt survival at 12 months of individual surgeons varied between 50 - 60 %, regardless of the number of years of experience of the surgeon; however, performance variability as measured by the standard deviation of 12 month survival rates for all surgeons, adjusted for years of experience, ranged widely until the fifth year of practice. The average number of procedures per year for treating hospitals was 2 with 75 %, providing 12 or fewer services annually. Over the entire study, 50 % of institutions provided 10 or fewer procedures. The mean institutional infection rate was 11.4 % (SD 23, median--6.0). CONCLUSIONS: Quality monitoring of infection rate and duration of shunt function remains critical as many surgeons and hospitals provide care to children with hydrocephalus infrequently. Variability in infection rates and shunt survival at 12 months are a function of surgeon experience, measured by years in practice. Variability in outcome decreases with increasing surgeon experience.

The treatment of cerebrospinal fluid shunt infections. Results from a practice survey of the American Society of Pediatric Neurosurgeons.

It is our impression that the management strategy for infected cerebrospinal fluid (CSF) shunts varies significantly among pediatric neurosurgeons. The purpose of this paper is to present the results of a practice survey on the treatment of shunt infections which was distributed to all active members of the American Society of Pediatric Neurosurgeons (ASPN). Eighty-four of 129 ASPN members (65%) responded to the survey. Most ASPN members remove the shunt and place an external ventricular drain (EVD) to treat Staphylococcus epidermidis (59.5%), S. aureus (64.3%) and gram-negative rod infections (67.9%). The second most common method of treatment was externalization of the shunt (33.3, 29.8 and 25%, respectively). The duration of antibiotic treatment was extremely variable. When the shunt was removed and an EVD inserted, the duration of antibiotic treatment for S. epidermidis and S. aureus ranged from 5 to 21 total days (2-21 days of sterile cultures). For gram-negative rod infections treated with shunt removal and an EVD, the total duration of antibiotic therapy ranged from 5 to 24 days (2-37 days of sterile cultures). The majority of ASPN members remove the infected CSF shunt and place an EVD for the management of shunt infections. Significant variation exists in the duration of antibiotic therapy. Determining the most effective duration of antibiotic therapy in an effort to shorten hospitalization and minimize complications without sacrificing efficacy will require further study.

Predicting shunt failure on the basis of clinical symptoms and signs in children.

OBJECT: In evaluating pediatric patients for shunt malfunction, predictive values for symptoms and signs are important in deciding which patients should undergo an imaging study, whereas determining clinical findings that correlate with a low probability of shunt failure could simplify management. METHODS: Data obtained during the recently completed Pediatric Shunt Design Trial (PSDT) were analyzed. Predictive values were calculated for symptoms and signs of shunt failure. To refine predictive capability, a shunt score based on a cluster of signs and symptoms was derived and validated using multivariate methods. Four hundred thirty-one patient encounters after recent shunt insertions were analyzed. For encounters that took place within 5 months after shunt insertion (early encounters), predictive values for symptoms and signs included the following: nausea and vomiting (positive predictive value [PPV] 79%, likelihood ratio [LR] 10.4), irritability (PPV 78%, LR 9.8), decreased level of consciousness (LOC) (PPV 100%), erythema (PPV 100%), and bulging fontanelle (PPV 92%, LR 33.1). Between 9 months and 2 years after shunt insertion (late encounters), only loss of developmental milestones (PPV 83%, LR 36.7) and decreased LOC (PPV 100%) were strongly associated with shunt failure. However, the absence of a symptom or sign still left a 15 to 29% (early encounter group) or 9 to 13% (late encounter group) chance of shunt failure. Using the shunt score developed for early encounters, which sums from 1 to 3 points according to the specific symptoms or signs present, patients with scores of 0, 1, 2, and 3 or greater had shunt failure rates of 4%, 50%, 75%, and 100%, respectively. Using the shunt score derived from late encounters, patients with scores of 0, 1, and 2 or greater had shunt failure rates of 8%, 38%, and 100%, respectively. CONCLUSIONS: In children, certain symptoms and signs that occur during the first several months following shunt insertion are strongly associated with shunt failure; however, the individual absence of these symptoms and signs offers the clinician only a limited ability to rule out a shunt malfunction. Combining them in a weighted scoring system improves the ability to predict shunt failure based on clinical findings.

Axillary nerve injuries in children.

Isolated axillary nerve injury is uncommon, particularly in children. The motor deficit of shoulder abduction may not recover spontaneously and can be a substantial handicap. Detection may be difficult initially, as the injury is masked by trauma such as head injury, and concomitant shoulder injury requiring immobilization. After mobilization, patients learn to partially compensate by using alternate muscles. There are few reports of surgical management of this nerve injury. Most concern predominantly adults, and the results are mixed with on average slightly greater than half having a good recovery (defined as grade 4-5 Medical Research Council muscle power). We present our experience with 4 pediatric patients who had axillary nerve injury. Three patients had an interposition nerve graft, and 1 patient underwent neurolysis. All patients recovered to grade 4-5 deltoid muscle power. Children with an axillary nerve injury which fails to recover spontaneously by 4-6 months should strongly be considered for surgical exploration.

Pediatric peri-insular hemispherotomy.

A number of surgical procedures are available for patients with epilepsy associated with diffuse hemispheric disorders. In this report, 16 pediatric patients had hemispherectomy: 5 underwent hemidecortication and 11 had peri-insular hemispherotomy. The clinical records were retrospectively reviewed, and the results and complications of the procedures were documented. The procedure was feasible in very young children and in the absence of ventriculomegaly.

The initial treatment of hydrocephalus: an assessment of surgeons' preference between third ventriculostomy and shunt insertion.

Third ventriculostomy is an option for patients who have traditionally received a ventriculoperitoneal shunt. This study has been conducted to determine: 1. How common is third ventriculostomy as the initial treatment of hydrocephalus? 2. Does the frequency of third ventriculostomy vary among surgeons? 3. What factors influence surgeons' decision to choose third ventriculostomy? Surgeons completed a questionnaire addressing patient selection and technique factors. Nine case scenarios were reviewed by surgeons who were then asked to choose a ventriculoperitoneal shunt or a third ventriculostomy as the initial treatment. Forty-three responses were received. The proportion of new patients treated with third ventriculostomy varied widely (0%-100%, median 13%). This was not related to years in practice, type of training or presence of residents/fellows. Factors that increased the chance of a third ventriculostomy were triventricular hydrocephalus on CT/MR, isolated aqueduct stenosis, thin ballooned floor and tectal tumor. Factors that decreased the chance of a third ventriculostomy were dilated subarachnoid spaces, meningitis and head injury. The presence of myelomeningocele or age < 1 year were less likely to influence the choice of operation. Variation in the rate of third ventriculostomy as the first treatment for hydrocephalus is large. It is unlikely that this degree of variation can be explained by differences in patient populations. Further work to refine and disseminate the indications for third ventriculostomy is warranted.

CSF shunts 50 years on--past, present and future.

Cerebrospinal fluid (CSF) shunts were invented almost 50 years ago. While their introduction revolutionized the treatment of hydrocephalus, their complications have become legendary, and the focus of much investigation and development of new devices. New devices have been based upon improved understanding of the pathophysiology of hydrocephalus or shunt complications. Despite the rational, or frequently "more physiological," functioning of these devices, all too often unexpected complications have ensued, and the initial enthusiasm for the devices has waned. Assessing the efficacy of the devices has been difficult, owing to the lack of properly conducted studies. Nevertheless, the overall impact of shunt design improvements has seemed very limited. A recent randomized trial of CSF shunt design, examining the failure rates of two new and widely used valves (the Cordis Orbis Sigma and the Medtronic PS Medical Delta valves) failed to find any advantage of these over standard valve designs, many of which have been used almost since the inception of CSF shunts. A search for risk factors for failure, in a post hoc analysis of the data, indicated only that the etiology of the hydrocephalus and the position and local environment of the ventricular catheter tip were probably important. Remarkably, the rate of change in the size of the ventricles and the final ventricular size were not different despite the substantial differences in flow characteristics of the two new valves. Shunt failure rates of less than 5% at 1 year, with infection rates of less than 1%, seem like reasonable goals for the next decade in the new millenium. This can be achieved through basic research into the pathophysiology of shunt failure with improved mathematical models, and perhaps animal models of shunt failure. Efficacy of new devices or treatments must be scrutinized scientifically so as not to waste valuable resources and time on unproven treatments. Uncontrolled series and testimonial assertions about new treatments or devices, especially from proponents with a vested interest, should be regarded with great skepticism. Nevertheless, our best efforts are likely to result in a major advance in the management of pediatric hydrocephalus, which now seems tantalizingly close.

Long-term follow-up data from the Shunt Design Trial.

BACKGROUND: A previously reported multicenter randomized trial assessed whether 2 new shunt valve designs would reduce shunt failure rates compared to differential pressure valves. The study did not show a significant difference in the time to first shunt failure. Patients entered the trial between October 1, 1993, and October 31, 1995. The primary results were based on the patients' status as of October 31, 1996 (a minimum follow-up of 1 year). This report describes the late complications based on the patients' most recent follow-up. METHODS: Three hundred and forty-four hydrocephalic children at 12 North American and European centers were randomized to 1 of 3 valves: a standard differential pressure valve; a Delta valve (PS Medical-Medtronic) or a Sigma valve (NMT Cordis). Patients were followed until their first shunt failure. Shunt failure was defined as shunt surgery for obstruction, overdrainage, loculation or infection. If the shunt did not fail, follow-up was continued until August 31, 1999. RESULTS: One hundred and seventy-seven patients had shunt failure. Shunt obstruction occurred in 131, overdrainage in 13, loculated ventricles in 2 and infection in 29. The overall shunt survival was 62% at 1 year, 52% at 2 years, 46% at 3 years, 41% at 4 years. The survival curves for the 3 valves were similar to those from the original trial and did not show a survival advantage for any particular valve. CONCLUSIONS: Prolonged follow-up to date does not alter the primary conclusions of the trial: there does not appear to be one valve that is clearly the best for the initial treatment of pediatric hydrocephalus.

The patterns of late deterioration in patients with transitional lipomyelomeningocele.

INTRODUCTION: Tethering is assumed to be the primary cause of deterioration seen in children with transitional lipomyelomeningocele as they age. The inevitability of deterioration has led to recommendations for prophylactic interventions to stabilize or prevent further clinical deterioration. OBJECTIVE: Determine the frequency and patterns of functional deterioration observed after successful untethering in patients with transitional lipomyelomeningocele and compare functional outcomes with what is known regarding untreated patients. METHODS: Fifty patients having transitional LMMC, treated at a single institution and followed in a multidisciplinary clinic were retrospectively reviewed to determine their clinical status prior to untethering, and the time to development of new symptoms or signs following untethering. RESULTS: 82% of patients were diagnosed and 78% underwent untethering prior to one year of age. All patients had a cutaneous lumbosacral lipoma, 22 patients were considered normal at presentation and 28 showed abnormalities on clinical examination. Forty-nine patients were untethered successfully and all were available for follow-up ranging from 2 to 138 months (mean 39 months). Acute morbidity was limited to transient neurogenic bladder dysfunction and minor wound complications. Late clinical deterioration occurred in the majority of patients. Orthopedic and neurological deterioration occurred over the first 60 months following untethering and urological deterioration occurred thereafter. CONCLUSIONS: Functional loss after untethering is common and the pattern of loss is likely a reflection of the ability to detect abnormalities in this infant population. Untethering does not usually result in permanent acute morbidity, and does not prevent longer-term functional deterioration. The ratio of asymptomatic to symptomatic patients at follow-up in this operative series is similar to age-matched historical series of untreated patients.

Change in ventricular size and effect of ventricular catheter placement in pediatric patients with shunted hydrocephalus.

OBJECTIVE: The multicenter, randomized pediatric cerebrospinal fluid shunt valve design trial found no difference in the rate of shunt failure between a standard valve, a siphon-reducing valve (Delta; Medtronic PS Medical, Goleta, CA), and a flow-limiting valve (Orbis Sigma; Cordis, Miami, FL); however, the valves were expected to have different effects on ultimate ventricular size. Also, the catheter position or local environment of the ventricular catheter tip might have affected shunt failure. Therefore, we performed a post hoc analysis to understand what factors, other than valve design, affected shunt failure and to identify strategies that might be developed to reduce shunt failure. METHODS: Ventricular size was measured at as many as six different intervals, using a modified Evans' ratio (with incorporation of the frontal and occipital dimensions), in 344 patients. Ventricular catheter location was defined as being in the frontal horn, occipital horn, body of the lateral ventricle, third ventricle, embedded in brain, or unknown. The ventricular catheter tip was described as surrounded by cerebrospinal fluid, touching brain, or surrounded by brain parenchyma within the ventricle (slit ventricle). Repeated measures analysis of variance for unbalanced data was used to analyze ventricular size. A Cox model (with incorporation of time-dependent covariates) was used to evaluate the contribution of age, etiology, shunt design, ventricular size, ventricular catheter location, and environment among the cases. RESULTS: Ventricular volume decreased in an exponential fashion, forming a plateau at 14 months, and was similar for the three valves (P = 0.4). Frontal and occipital ventricular catheter tip locations were associated with a reduced risk of shunt failure (hazard ratios, 0.60 [P = 0.02] and 0.45 [P = 0.001], respectively). Ventricular catheter tips surrounded by cerebrospinal fluid or touching the brain were associated with a reduced risk of failure (hazard ratios, 0.21 and 0.33, respectively; P = 0.0001). Patients with myelomeningocele or large ventricles had increased risk of malfunction (hazard ratios, 1.78 [P = 0.006] and 2.33 [P = 0.03], respectively). CONCLUSION: Decline of ventricular size over time is not affected by these different shunt valve designs. This suggests that the mechanical models of hydrocephalus on which the designs were based are inadequate. Ventricular catheter tip location and ventricular catheter environment are important. Techniques to accurately place ventricular catheters and new valve designs that effectively control ventricular size might reduce shunt malfunction.

Clinical trials.

The randomized clinical trial (RCT) is often referred to as the gold standard for the assessment of treatment efficacy. RCTs are receiving greater attention in the literature and higher priority by funding agencies than they have in the past. In this paper, the basic principles of clinical trial design are reviewed using examples from the neurosurgical literature. The importance of designing the trial to answer one question well is emphasized.

The shunt design trial: variation in surgical experience did not influence shunt survival.

INTRODUCTION: An international multicenter randomized trial comparing standard pressure differential valves, Orbis Sigma valves and PS Medical Delta valves for children with newly diagnosed hydrocephalus failed to show a difference in the time to first shunt failure. Surgeons' prior experience with the three valves varied. This analysis was performed to assess whether lack of surgical experience with any of the valves could explain the overall negative result. METHODS: (1) Shunt survival was compared at high- and low-volume centers. (2) The 1-year shunt survival rates (+/-95% confidence interval) for patients entered in the first quarter and the last quarter of the 25-month accrual period were compared (for all patients, and for each shunt). RESULTS: Survival curves for high- and low-volume centers were similar. Ninety of the 344 randomized patients were accrued in the first quarter and 93 in the last quarter. The 1-year shunt survival for all patients entered in the first quarter was 72% (+/-11%) compared to 64% (+/-10%) for patients entered in the last quarter. The shunt-specific results were 66% (+/-20%) compared to 54% (+/-20%) for Delta valve patients, 75% (+/-20%) compared to 70% (+/-17%) for standard valve patients and 76% (+/-18%) compared to 66% (+/-16%) for Orbis Sigma patients. DISCUSSION: Shunt survival did not improve as surgeons accumulated experience over the course of the study. Although participating surgeons had varying levels of experience with the different shunts at the start of the trial, this does not appear to explain the overall negative trial result.

Efficacy and complications of morphine infusions in postoperative paediatric patients.

The aim of the study was to evaluate the efficacy and the incidence of clinically significant adverse drug reactions (ADRs) in paediatric patients receiving continuous intravenous morphine infusions for acute postoperative pain. Definitions were established for ADRs and data were collected in an immediately retrospective fashion for a maximum of 72 h in 110 patients >/=5 three months of age (0.3-16.7 years) receiving morphine infusions and admitted to a general ward over a three month convenience sampling period. Inadequate analgesia occurred in 65.5% of patients during the first 24 h of therapy and occurred most frequently in patients with infusion rates of 20 microg.kg-1.h-1 or less. Nausea/vomiting was the most commonly experienced ADR (42.5%). The incidence of respiratory depression was 0% (95% CI=0-3.3%). Other ADRs included: urinary retention (13.5%), pruritus (12.7%), dysphoria (7.3%), hypoxaemia (4.5%), discontinuation of morphine for treatment of an ADR (3.6%), and difficulty in arousal (0.9%). The most common ADRs associated with morphine infusions were inadequate analgesia (in the first 24 h) and nausea/vomiting. There were no cases of respiratory depression. Methods of avoiding initial inadequate analgesia and treating nausea and vomiting associated with morphine infusions are needed.

An assessment of observer bias in the shunt design trial.

INTRODUCTION: An international multicenter randomized trial comparing standard pressure differential valves, Orbis Sigma valves and PS Medical Delta valves, for children with newly diagnosed hydrocephalus failed to show a difference in the time to first shunt failure (power 80%). In order to avoid observer bias, the primary endpoint, shunt failure, was defined by detailed clinical and radiological criteria. Surgeons notified the data center when their patient reached endpoint. Their decision was blindly reviewed by a centralized adjudication process. The current analysis asks: (1) Did the surgeons and the blinded adjudication process agree on the presence of shunt failure? (2) Do the shunt survival curves change when the surgeons' assessment of outcome is used? METHODS: The two methods of outcome assessment (surgeons' decision and adjudication process) were compared with a kappa statistic for the presence of shunt failure and a log rank statistic for time to shunt failure. RESULTS: The surgeon and the adjudication process agreed on the presence of the primary outcome in 313/344 patients in the trial (kappa = 0.81). The 31 cases of disagreement were evenly distributed among the three shunts. The survival curves generated from the surgeons' decision were not significantly different from those generated by the adjudication process (log rank = 0.70, p = 0.37) and did not alter the study conclusions. DISCUSSION: Observer bias in the assessment of outcome is always a concern in an unblinded clinical trial such as this one. We did not detect an observer bias of sufficient magnitude to alter the study conclusions.

Randomized trial of cerebrospinal fluid shunt valve design in pediatric hydrocephalus.

OBJECTIVE: Forty percent of standard cerebrospinal fluid shunts implanted for the treatment of pediatric hydrocephalus fail within the first year. Two new shunt valves designed to limit excess flow, particularly in upright positions, were studied to compare treatment failure rates with those for standard differential-pressure valves. METHODS: Three hundred-forty-four hydrocephalic children (age, birth to 18 yr) undergoing their first cerebrospinal fluid shunt insertion were randomized at 12 North American or European pediatric neurosurgical centers. Patients received one of three valves, i.e., a standard differential-pressure valve; a Delta valve (Medtronic PS Medical, Goleta, CA), which contains a siphon-control component designed to reduce siphoning in upright positions; or an Orbis-Sigma valve (Cordis, Miami, FL), with a variable-resistance, flow-limiting component. Patients were monitored for a minimum of 1 year. Endpoints were defined as shunt failure resulting from shunt obstruction, overdrainage, loculations of the cerebral ventricles, or infection. Outcome events were assessed by blinded independent case review. RESULTS: One hundred-fifty patients reached an endpoint; shunt obstruction occurred in 108 (31.4%), overdrainage in 12 (3.5%), loculated ventricles in 2 (0.6%), and infection in 28 (8.1%). Sixty-one percent were shunt failure-free at 1 year and 47% at 2 years, with a median shunt failure-free duration of 656 days. There was no difference in shunt failure-free duration among the three valves (P = 0.24). CONCLUSION: Cerebrospinal fluid shunt failure, predominantly from shunt obstruction and infection, remains a persistent problem in pediatric hydrocephalus. Two new valve designs did not significantly affect shunt failure rates.

Effect of hyperventilation on regional cerebral blood flow in head-injured children.

OBJECTIVES: To study cerebral blood flow and cerebral oxygen consumption in severe head-injured children and also to assess the effect of hyperventilation on regional cerebral blood flow. DESIGN: Prospective cohort study. SETTING: Pediatric intensive care unit at a tertiary-level university children's hospital. PATIENTS: Twenty-three children with isolated severe brain injury, whose admission Glasgow Coma Scores were <8. INTERVENTIONS: PaCO2 was adjusted by altering minute ventilation. Cerebral metabolic measurements were made at three levels of PaCO2 (>35, 25 to 35, and <25 torr [>4.7, 3.3 to 4.7, and <3.3 kPa]) after allowing 15 mins for equilibrium. MEASUREMENTS AND MAIN RESULTS: Thirty-eight studies (each study consisting of three sets of measurements at different levels of PaCO2) were performed on 23 patients. At each level of PaCO2, the following measurements were made: xenon-enhanced computed tomography scans; cerebral blood flow; intracranial pressure; jugular venous bulb oxygen saturation; mean arterial pressure; and arterial oxygen saturation. Derived variables included: cerebral oxygen consumption; cerebral perfusion pressure; and oxygen extraction ratio. Cerebral blood flow decreased below normal after head injury (mean 49.6 +/- 14.6 mL/min/100 g). Cerebral oxygen consumption decreased out of proportion to the decrease in cerebral blood flow; cerebral oxygen consumption was only a third of the normal range (mean 1.02 +/- 0.59 mL/min/100 g). Neither cerebral blood flow nor cerebral oxygen consumption showed any relationship to time after injury, Glasgow Coma Score at the time of presentation, or intracranial pressure. The frequency of one or more regions of ischemia (defined as cerebral blood flow of <18 mL/min/100 g) was 28.9% during normocapnia. This value increased to 73.1% for PaCO2 at <25 torr. CONCLUSIONS: Severe head injury in children produced a modest decrease in cerebral blood flow but a much larger decrease in cerebral oxygen consumption. Absolute hyperemia was uncommon at any time, but measured cerebral blood flow rates were still above the metabolic requirements of most children. The clear relationship between the frequency of cerebral ischemia and hypocarbia, combined with the rarity of hyperemia, suggests that hyperventilation should be used with caution and monitored carefully in children with severe head injuries.

Therapeutic electrical stimulation following selective posterior rhizotomy in children with spastic diplegic cerebral palsy: a randomized clinical trial.

A randomized controlled trial was carried out to determine the effectiveness of therapeutic electrical stimulation (TES) in improving the function of children with spastic cerebral palsy (CP), who had undergone selective posterior lumbosacral rhizotomy more than a year previously. Children were randomly assigned to groups to receive TES for 1 year, or to have no TES. The primary outcome was the change in the Gross Motor Function Measure (GMFM), a quantitative and validated measure for use in children with spastic CP. There was a statistically significant and clinically important improvement in outcome for the treated children, with the mean change in the GMFM score at one year being 5.5% compared with 1.9% in the untreated group (P = 0.001). TES was simple to use, had no significant complications, and was well accepted by the children and their caregivers, as indicated by an average compliance of 93% for the application of TES on a nightly basis over the course of the study. It was concluded that TES may be beneficial in children with spastic CP who have undergone a selective posterior rhizotomy procedure more than 1 year previously.