A Pressure Adjustment Protocol for Programmable Valves

OBJECTIVE: There is no definite adjustment protocol for patients shunted with programmable valves. Therefore, we attempted to find an appropriate method to adjust the valve, initial valve-opening pressure, adjustment scale, adjustment time interval, and final valve-opening pressure of a programmable valve. METHODS: Seventy patients with hydrocephalus of various etiologies were shunted with programmable shunting devices (Micro Valve with RICKHAM(R) Reservoir). The most common initial diseases were subarachnoid hemorrhage (SAH) and head trauma. Sixty-six patients had a communicating type of hydrocephalus, and 4 had an obstructive type of hydrocephalus. Fifty-one patients had normal pressure-type hydrocephalus and 19 patients had high pressure-type hydrocephalus. We set the initial valve pressure to 10-30 mmH2O, which is lower than the preoperative lumbar tapping pressure or the intraoperative ventricular tapping pressure, conducted brain computerized tomographic (CT) scans every 2 to 3 weeks, correlated results with clinical symptoms, and reset valve-opening pressures. RESULTS: Initial valve-opening pressures varied from 30 to 180 mmH2O (mean, 102 +/- 27.5 mmH2O). In high pressure-type hydrocephalus patients, we have set the initial valve-opening pressure from 100 to 180 mmH2O. We decreased the valve-opening pressure 20-30 mmH2O at every 2- or 3-week interval, until hydrocephalus-related symptoms improved and the size of the ventricle was normalized. There were 154 adjustments in 81 operations (mean, 1.9 times). In 19 high pressure-type patients, final valve-opening pressures were 30-160 mmH2O, and 16 (84%) patients' symptoms had nearly improved completely. However, in 51 normal pressure-type patients, only 31 (61%) had improved. Surprisingly, in 22 of the 31 normal pressure-type improved patients, final valve-opening pressures were 30 mmH2O (16 patients) and 40 mmH2O (6 patients). Furthermore, when final valve-opening pressures were adjusted to 30 mmH2O, 14 patients symptom was improved just at the point. There were 18 (22%) major complications : 7 subdural hygroma, 6 shunt obstructions, and 5 shunt infections. CONCLUSION: In normal pressure-type hydrocephalus, most patients improved when the final valve-opening pressure was 30 mmH2O. We suggest that all normal pressure-type hydrocephalus patients be shunted with programmable valves, and their initial valve-opening pressures set to 10-30 mmH2O below their preoperative cerebrospinal fluid (CSF) pressures. If final valve-opening pressures are lowered in 20 or 30 mmH2O scale at 2- or 3-week intervals, reaching a final pressure of 30 mmH2O, we believe that there is a low risk of overdrainage syndromes.

Subdural Hematoma following Minor Head Trauma in Patients with Ventriculoperitoneal Shunts : Two Case Reports / The Japanese Journal of Rehabilitation Medicine

Subdural hematoma or effusion is a common complication in ventriculoperitoneal shunts. However, the incidence of subdural hematoma in shunted patients requiring a surgical procedure has been decreasing recently, since it can be treated with a newly developed pressure-programmable valve system. We treated two shunted patients with subdural hematomas caused by simple falls during gait training. The management was complicated, involving multiple surgical procedures. Case 1 : A 65-year-old woman, who had undergone ventriculoperitoneal shunting for normal pressure hydrocephalus after removal of a meningioma, suffered mild head trauma due to a fall during gait training and developed consciousness disturbance after 2 hours. Computed tomography revealed an acute subdural hematoma with marked midline shift. Emergency craniotomy and hematoma evacuation were performed. Case 2 : A 61-year-old man, who had previously undergone ventriculoperitoneal shunting for normal pressure hydrocephalus after subarachnoid hemorrhage, fell to the floor during gait training. Computed tomography demonstrated a thin subdural hematoma, thus the pressure-programmable valve was adjusted to a higher pressure. However, the hematoma continued to enlarge and his level of consciousness deteriorated. Consequently, shunt ligation and irrigation of the chronic subdural hematoma were performed 6 days after the head trauma. Brain atrophy and a lowering of the intracranial pressure, which are both shunt-related complications, may have contributed to these patient's subdural hematomas forming after such relatively minor head traumas. In conclusion, rehabilitation physicians treating shunted patients must be aware of the possibility of a catastrophic intracranial hemorrhage following minor head trauma and of the various treatment-related difficulties arising in such a scenario including exacerbation of hydrocephalus, meningitis, and rebleeding.

Clinical Analysis of Programmable Valve versus Differential Pressure Valve in Hydrocephalus

OBJECTIVE: The goal of this study is to assess the safety and efficacy of the Codman Hakim programmable valve versus differential pressure valve in the treatment of patients with hydrocephalus. METHODS: The authors conducted a retrospective study of 83 patients who were implanted the Codmam Hakim programmable valve and differential pressure valve between January 1996 and April 2001. We analyzed complications, the number of shunt revision, and prognosis between the two groups. We analyzed initial pressure setting, the cause of reprogramming, and the number of reprogramming in Codman Hakim programmable valve. RESULTS: No statistically significant difference was apparent between the Codmam Hakim programmable valve group and a differential pressure valve group in complications, primary disease entities in shunt revision cases and prognosis(p>0.05). And statistically difference was not apparent in the number of shunt revision(p=0.07). The average pressure and range of initial pressure setting in the Codmam Hakim programmable valve was 97.1mmH2O and 50~150mmH2O, respectively. The number of cases of reprogragmming in the Codmam Hakim programmable valve was 12 in total, 1 time in 9 cases , 2 times in 2 cases, and 3 times in 1case. CONCLUSION: The Codmam Hakim programmable valve can decrease shunt revision caused by underdrainage and overdrainage complications. The optimal pressure settting is the key point to decreasing reprogramming and complications in the Codmam Hakim programmable valve and a differential pressure valve.

Clinical Experience with the Programmable Valve for Hydrocephalus Patients

OBJECTIVE: The goal of this study is to establish the value of the programmable valve system. METHODS: The authors conducted a single center retrospective study of 41 consecutive patients who had undergone ventriculoperitoneal shunt with programmable valve for hydrocephalus of various etiology from March 1999 to February 2002. RESULTS: In 10 patients(24%), valve pressure adjustment was required at least 3 times or more for the reason of underdrainage or overdrainage. The range of pressure reprogramming was 10 to 120mmH2O. The clinical symptoms improved in 37 patients(90%). The radiologic improvement was obtained in 88%. Shunt was minimally functioning in 3 cases without any clinical effect at the pressure of 30mmH2O. CONCLUSION: The programmable valve has been particularly useful in changing ventricular size for the correction of overdrainage or underdranage by the easy control of valve pressure without any invasive procedure. The authors' preference is to use the programmable valve system for all conditions.

The Use of the Programmable Valve Shunt System in the Management of Patients with Hydrocephalus

OBJECTIVE: The goal of this study was to clarify the value of the programmable valve shunt system to readjust the pressure noninvasively for the adequate cerebrospinal fluid(CSF) drainage. METHODS: The authors analyzed a single-center retrospective study of 54 patients suffering from hydrocephalus of various causes, as aneurysm(21 patients), trauma(13 patients), normal-pressure hydrocephalus(NPH, 7 patients) and so on. In 51 cases a programmable valve was implanted at the first shunt implantation. In three cases the shunt was replaced to a programmable valve system. RESULTS: In 33 patients(61%) of cases valve pressure adjustment was required at least once(total number of readjustment 54, mean 1.7, maximum 5) for the reason of underdrainage(36) or overdrainge(18). The range of reprogrammed valve pressure was 10 to 90mmH2O(mean 11.1+/-15.9mmH2O), the radiological finding improved 48.6% of frontal horn index at the beginning of reprogramming to 41.3%, and the clinical symptom related with hydrocephalus improved in 29 patients(87.8%) of pressure adjustment. Shunt reprogramming was necessary in patients with congenital hydrocephalus(100%), aneurysm(55%), NPH(71%), trauma(50%); the programmable valve proved particularly beneficial for overdrainge as subdural hygroma. CONCLUSION: The programmable valve was useful for the correction of overdrainge or underdrainage by the easy control of valve pressure without any invasive procedure.

Effectiveness of the Medos Hakim Programmable Valve in the Treatment of Various Type of Hydrocephalus

OBJECTIVE: To evaluate the advantages of Medos Hakim programmable valve system in the treatment of various type of hydrocephalus. MATERIALS AND METHODS: We retrospectively analyzed 33 patients who underwent ventriculoperitoneal shunt with Medos Hakim programmable valve system from December 1995 to June 1998. They were followed from 1 month to 35 months(mean 10.6 months). RESULTS: The overall outcome were excellent in 8 patients, improvement but residual symptoms in 16 patients and unchanged in 9 patients. There were 8 complications; overdrainage with subdural fluid collections(4 cases), infections(2 cases), obstruction(1 case) and mechanical failure(1 case). Overdrainage with subdural fluid collections was managed by readjustment of valve operating pressure alone in 3 cases and by observation in 1 case. Readjustment of valve pressure was needed more in children than in adults. There was significant correlation between opening and final pressure and the opening pressure was important for choosing the initial valve operating pressure at the time of implantation. CONCLUSION: In this study, we found that the Medos Hakim programmable valve is beneficial in cases with slowly progressive hydrocephalus and very large ventricles, especially in children, in order to normalize the ventricle size slowly with avoiding subdural hygromas.