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.
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.
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.
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.
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.
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.
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.
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).
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.