Management of cerebrospinal fluid pseudocysts in the laparoscopic age.

OBJECTIVE: Abdominal CSF pseudocysts are an uncommon but challenging complication of ventriculoperitoneal shunts. Pseudocysts consist of a loculated intraperitoneal compartment that inadequately absorbs CSF and may be infected or sterile at diagnosis. The treatment goal is to clear infection if present, reduce inflammation, and reestablish long-term function in an absorptive (intraperitoneal) space. This aim of this paper was to study the efficacy of primary laparoscopic repositioning of the distal shunt catheter for treatment of sterile abdominal CSF pseudocysts. METHODS: All patients treated for abdominal CSF pseudocysts at Dallas Children's Health from 1991 to 2021 were retrospectively reviewed. Patient history and pseudocyst characteristics were analyzed, with a primary outcome of pseudocyst recurrence at 1 year. RESULTS: Of 92 primary pseudocysts, 5 initial treatment strategies (groups) were used depending on culture status, clinical history, and surgeon preference: 1) shunt explant/external ventricular drain (EVD) placement (23/92), 2) distal tubing externalization (13/92), 3) laparoscopic repositioning (35/92), 4) open repositioning (4/92), and 5) other methods such as pseudocyst drainage or direct revision to another terminus (17/92). Seventy pseudocysts underwent shunt reimplantation in the peritoneal space. The 1-year peritoneal shunt survival for groups 1 and 2 combined was 90%, and 62% for group 3. In group 3, 1-year survival was better for those with normal systemic inflammatory markers (100%) than for those with high markers (47%) (p = 0.042). In a univariate Cox proportional hazards model, the risk of pseudocyst recurrence was increased if the most recent abdominal procedure was a nonshunt abdominal surgery (p = 0.012), and it approached statistical significance with male sex (p = 0.054) and elevated inflammatory markers (p = 0.056. Multivariate Cox analysis suggested increased recurrence risk with male sex (p = 0.05) and elevated inflammatory markers (p = 0.06), although the statistical significance threshold was not reached. The length of hospital stay was shorter for laparoscopic repositioning (6 days) than for explantation/EVD placement (21 days) (p < 0.0001). Ultimately, 62% of patients had a peritoneal terminus at the last follow-up, 33% (n = 30) had an extraperitoneal terminus (19 pleura, 8 right heart, and 3 gallbladder), and 5 patients were shunt free. CONCLUSIONS: Some sterile pseudocysts with normal systemic inflammatory markers can be effectively treated with laparoscopic repositioning, resulting in a significantly shorter hospitalization and modestly higher recurrence rate than shunt explantation.

Cerebellar tonsil reduction for surgical treatment of Chiari malformation type I in children.

OBJECTIVE: The goal of this study was to review the efficacy and safety of different surgical techniques used for treatment of Chiari malformation type I (CM-I) in children. METHODS: The authors retrospectively reviewed 437 consecutive children surgically treated for CM-I. Procedures were classified into four groups: bone decompression (posterior fossa decompression [PFD]) and duraplasty (PFD with duraplasty [PFDD]), PFDD with arachnoid dissection (PFDD+AD), PFDD with tonsil coagulation of at least one cerebellar tonsil (PFDD+TC), and PFDD with subpial tonsil resection of at least one tonsil (PFDD+TR). Efficacy was measured as a greater than 50% reduction in the syrinx by length or anteroposterior width, patient-reported improvement in symptoms, and rate of reoperation. Safety was measured as the rate of postoperative complications. RESULTS: The mean patient age was 8.4 years (range 3 months to 18 years). In total, 221 (50.6%) patients had syringomyelia. The mean follow-up was 31.1 months (range 3-199 months), and there was no statistically significant difference between groups (p = 0.474). Preoperatively, univariate analysis showed that non-Chiari headache, hydrocephalus, tonsil length, and distance from the opisthion to brainstem were associated with the surgical technique used. Multivariate analysis demonstrated that hydrocephalus was independently associated with PFD+AD (p = 0.028), tonsil length was independently associated with PFD+TC (p = 0.001) and PFD+TR (p = 0.044), and non-Chiari headache was inversely associated with PFD+TR (p = 0.001). In the treatment groups postoperatively, symptoms improved in 57/69 (82.6%) PFDD patients, 20/21 (95.2%) PFDD+AD patients, 79/90 (87.8%) PFDD+TC patients, and 231/257 (89.9%) PFDD+TR patients, and differences between groups were not statistically significant. Similarly, there was no statistically significant difference in postoperative Chicago Chiari Outcome Scale scores between groups (p = 0.174). Syringomyelia improved in 79.8% of PFDD+TC/TR patients versus only 58.7% of PFDD+AD patients (p = 0.003). PFDD+TC/TR remained independently associated with improved syrinx outcomes (p = 0.005) after controlling for which surgeon performed the operation. For those patients whose syrinx did not resolve, no statistically significant differences between surgery groups were observed in the length of follow-up or time to reoperation. Overall, there was no statistically significant difference between groups in postoperative complication rates, including aseptic meningitis and CSF- and wound-related issues, or reoperation rates. CONCLUSIONS: In this single-center retrospective series, cerebellar tonsil reduction, by either coagulation or subpial resection, resulted in superior reduction of syringomyelia in pediatric CM-I patients, without increased complications.

Margin-Free Fractionated Stereotactic Radiation Therapy for Pediatric Brain Tumors.

PURPOSE: Conventional radiation therapy (RT) to pediatric brain tumors exposes a large volume of normal brain to unwarranted radiation causing late toxicity. We hypothesized that in well demarcated pediatric tumors lacking microscopic extensions, fractionated stereotactic RT (SRT), without target volume expansions, can reduce high dose normal tissue irradiation without affecting local control. METHODS AND MATERIALS: Between 2008 and 2017, 52 pediatric patients with brain tumors were treated using the CyberKnife (CK) with SRT in 180 to 200 cGy per fraction. Thirty representative cases were retrospectively planned for intensity modulated RT (IMRT) with 4-mm PTV expansion. We calculated the volume of normal tissue within the high or intermediate dose region adjacent to the target. Plan quality and radiation dose-volume dosimetry parameters were compared between CK and IMRT plans. We also reported overall survival, progression-free survival (PFS), and local control. RESULTS: Tumors included low-grade gliomas (n = 28), craniopharyngiomas (n = 16), and ependymomas (n = 8). The volumes of normal tissue receiving high (≥80% of prescription dose or ≥40 Gy) or intermediate (80% > dose ≥50% of the prescription dose or 40 Gy > dose ≥25 Gy) dose were significantly smaller with CK versus IMRT plans (P < .0001 for all comparisons). With a median follow-up of 3.7 years (range, 0.1-9.0), 3-year local control was 92% for all patients. Eight failures occurred: 1 craniopharyngioma (marginal), 2 ependymomas (both in-field), and 5 low-grade gliomas (2 in-field, 1 marginal, and 2 distant). CONCLUSIONS: Fractionated SRT using CK without target volume expansion appears to reduce the volume of irradiated tissue without majorly compromising local control in pediatric demarcated brain tumors. These results are hypothesis generating and should be tested and validated in prospective studies.

A Novel Technique for Distal Shunt Revision: Retrospective Analysis of Guidewire-Assisted Distal Catheter Replacement.

BACKGROUND: Ventriculoperitoneal shunt revision is a common procedure. Disconnection and fracture of the distal catheter remain a common cause of ventriculoperitoneal shunt malfunction. OBJECTIVE: To describe a novel procedure for peritoneal replacement of the distal catheter by using a guidewire and a modified Seldinger technique (guidewire-assisted distal catheter replacement) and retrospectively evaluate the results of the surgical procedure. METHODS: Between September 2005 and December 2013, 68 patients were treated by a single surgeon (DMW) with distal catheter replacement using our technique. In brief, the previously placed distal catheter was exposed at its entry site into the abdomen. A soft guidewire with hydrophilic coating was inserted down the distal catheter into the peritoneum. The distal catheter was then removed over the guidewire, leaving the guidewire in place. A peel-away sheath and dilator were then inserted over the guidewire, and the dilator and guidewire were removed. The new distal catheter was then passed from the valve to the abdomen and was then fed through the peel-away sheath into the peritoneum. Charts were retrospectively reviewed for preoperative presentation, operative technique, and postoperative outcome. Records were specifically examined for any early or late complications. RESULTS: The mean patient age at surgery was 13 years. No immediate acute complications were noted. Of the 68 total patients, 45 patients had more than 6 months of follow-up. Of the 68 patients, 7 patients required another distal revision after guidewire-assisted distal catheter replacement. CONCLUSION: Distal shunt malfunction due to a mechanical failure is a common reason for shunt revision. We describe a technique for guidewire-assisted distal catheter replacement.

The use of abdominal binders to treat over-shunting headaches.

OBJECT: Headaches are common in children with shunts. Headaches associated with over-shunting are typically intermittent and tend to occur later in the day. Lying down frequently makes the headaches better. This paper examines the efficacy of using abdominal binders to treat over-shunting headaches. METHODS: Over an 18-year period, the senior author monitored 1027 children with shunts. Office charts of 483 active patients were retrospectively reviewed to identify those children with headaches and, in particular, those children who were thought to have headaches as a result of over-shunting. Abdominal binders were frequently used to treat children with presumed over-shunting headaches, and these data were analyzed. RESULTS: Of the 483 patients undergoing chart review, 258 (53.4%) had headache. A clinical diagnosis of over-shunting was made in 103 patients (21.3% overall; 39.9% of patients with headache). In 14 patients, the headaches were very mild (1-2 on a 5-point scale) and infrequent (1 or 2 per month), and treatment with an abdominal binder was not thought indicated. Eighty-nine patients were treated with a binder, but 19 were excluded from this retrospective study for noncompliance, interruption of the binder trial, or lack of follow-up. The remaining 70 pediatric patients, who were diagnosed with over-shunting headaches and were treated with abdominal binders, were the subjects of a more detailed retrospective study. Significant headache improvement was observed in 85.8% of patients. On average, the patients wore the binders for approximately 1 month, and headache relief usually persisted even after the binders were discontinued. However, the headaches eventually did recur in many of the patients more than a year later. In these patients, reuse of the abdominal binder was successful in relieving headaches in 78.9%. CONCLUSIONS: The abdominal binder is an effective, noninvasive therapy to control over-shunting headaches in most children. This treatment should be tried before any surgery is considered. It is suggested that the abdominal binder may modulate abnormally increased intracranial pulse pressures associated with over-shunting. Interactions with the cerebrovascular bed are suspected to account for persistent headache relief after the binder is discontinued.

Screw fixation of the upper cervical spine in the pediatric population. Clinical article.

OBJECT: Rigid fixation of the upper cervical spine has become an established method of durable stabilization for a variety of craniocervical pathological entities in children. In children, specifically, the use of C1-2 transarticular screws has been proposed in recent literature to be the gold standard configuration for pathology involving these levels. The authors reviewed the use of rigid fixation techniques alternative to C1-2 transarticular screws in children. Factors evaluated included ease of placement, complications, and postoperative stability. METHODS: Seventeen patients, ranging in age from 3 to 17 years (mean 9.6 years), underwent screw fixation involving the atlas or axis for a multitude of pathologies, including os odontoideum, Down syndrome, congenital instability, iatrogenic instability, or posttraumatic instability. All patients had preoperative instability of the occipitocervical or atlantoaxial spine demonstrated on dynamic lateral cervical spine radiographs. All patients also underwent preoperative CT scanning and MR imaging to evaluate the anatomical feasibility of the selected hardware placement. Thirteen patients underwent C1-2 fusion, and 4 underwent occipitocervical fusion, all incorporating C-1 lateral mass screws, C-2 pars screws, and/or C-2 laminar screws within their constructs. Patients who underwent occipitocervical fusion had no instrumentation placed at C-1. One patient's construct included sublaminar wiring at C-2. All patients received autograft onlay either from from rib (in 15 patients), split-thickness skull (1 patient), or local bone harvested within the operative field (1 patient). Nine patients' constructs were supplemented with recombinant human bone morphogenetic protein at the discretion of the attending physician. Eight patients had surgical sacrifice of 1 or both C-2 nerve roots to better facilitate visualization of the C-1 lateral mass. One patient was placed in halo-vest orthosis postoperatively, while the rest were maintained in rigid collars. RESULTS: All 17 patients underwent immediate postoperative CT scanning to evaluate hardware placement. Follow-up was achieved in 16 cases, ranging from 2 to 39 months (mean 14 months), and repeated dynamic lateral cervical spine radiography was performed in these patients at the end of their follow-up period. Some, but not all patients, also underwent delayed postoperative CT scans, which were done at the discretion of the treating attending physician. No neurovascular injuries were encountered, no hardware revisions were required, and no infections were seen. No postoperative pain was seen in patients who underwent C-2 nerve root sacrifice. Stability was achieved in all patients postoperatively. In all patients who underwent delayed postoperative CT scanning, the presence of bridging bone was shown spanning the fused levels. CONCLUSIONS: Screw fixation of the atlas using lateral mass screws, in conjunction with C-2 root sacrifice in selected cases, and of the axis using pars or laminar screws is a safe method for achieving rigid fixation of the upper cervical spine in the pediatric population.

Robotically guided radiosurgery for children.

BACKGROUND: A robotically guided linear accelerator has recently been developed which provides frameless radiosurgery with high precision. Potential advantages for the pediatric population include the avoidance of the cognitive decline associated with whole brain radiotherapy, the ability to treat young children with thin skulls unsuitable for frame-based methods, and the possible avoidance of general anesthesia. We report our experience with this system (the "Cyberknife") in the treatment of 21 children. PROCEDURES: Cyberknife radiosurgery was performed on 38 occasions for 21 patients, age ranging from 8 months to 16 years (7.0 +/- 5.1 years), with tumors considered unresectable. Three had pilocytic astrocytomas, two had anaplastic astrocytomas, three had ependymomas (two anaplastic), four had medulloblastomas, three had atypical teratoid/rhabdoid tumors, three had craniopharyngiomas, and three had other pathologies. The mean target volume was 10.7 +/- 20 cm(3), mean marginal dose was 18.8 +/- 8.1 Gy, and mean follow-up is 18 +/- 11 months. Twenty-seven (71%) of the treatments were single-shot and eight (38%) patients did not require general anesthesia. RESULTS: Local control was achieved in the patients with pilocytic and anaplastic astrocytoma, three of the patients with medulloblastoma, and the three with craniopharyngioma, but not for those with ependymoma. Two of the patients with rhabdoid tumors are alive 16 and 35 months after this diagnosis. There have been no procedure related deaths or complications. CONCLUSION: Cyberknife radiosurgery can be used to achieve local control for some children with CNS tumors without the need for rigid head fixation.