Twist-Drill or Burr Hole Craniostomy for Draining Chronic Subdural Hematomas: How to Choose It for Chronic Subdural Hematoma Drainage / 대한신경손상학회지

OBJECTIVE: Although twist-drill craniostomy (TDC) has a number of procedural advantages and an equivalent outcome compared to burr hole craniostomy (BHC) for the treatment of chronic subdural hematomas (CSDHs), the latter technique remains the preferred method. We analyzed symptomatic CSDHs in whom TDC at the pre-coronal suture entry point (PCSEP) was the primary method for hematoma drainage and BHC on the parietal was the secondary option. METHODS: CSDHs in 86 consecutive patients were included. TDC at the PCSEP, which is 1 cm anterior to coronal suture at the level of the superior temporal line, was the primary operational technique when the hematoma thickness was suitable, and BHC was performed via the parietal when TDC was unreasonable or failed. The clinical feasibility and outcomes of these approaches were analyzed. RESULTS: Of the 86 patients, 68 (79.1%) were treated by TDC, and 18 (20.9%) by BHC. All patients showed improvements in their symptoms after hematoma drainage. Neither morbidity nor mortality was associated with either technique, and there were no differences in drainage days between the groups. Ten patients had bilateral hematomas and were treated using TDC. Two patients were not sufficiently treated by TDC and, as a result, BHC was applied. Only six hematomas (7% of 86 hematomas) exhibited insufficient thickness on the computed tomography to perform TDC. CONCLUSION: When the hematoma was thick enough, a majority of the CSDHs were drained using TDC at the PCSEP as the first procedure, which was especially useful for bilateral hematomas and in elderly patients.

Comparison of the Indications and Treatment Results of Burr-Hole Drainage at the Maximal Thickness Area versus Twist-Drill Craniostomy at the Pre-Coronal Point for the Evacuation of Symptomatic Chronic Subdural Hematomas

OBJECTIVE: To analyze the clinical data and surgical results from symptomatic chronic subdural hematoma (CSDH) patients who underwent burr-hole drainage (BHD) at the maximal thickness area and twist-drill craniostomy (TDC) at the precoronal point. METHODS: We analyzed data from 65 symptomatic CSDH patients who underwent TDC at the pre-coronal point or BHD at the maximal thickness area. For TDC, we defined the pre-coronal point to be 1 cm anterior to the coronal suture at the level of the superior temporal line. TDC was performed in patients with CSDH that extended beyond the coronal suture, as confirmed by preoperative CT scans. Medical records, radiological findings, and clinical performance were reviewed and analyzed. RESULTS: Of the 65 CSDH patients, 13/17 (76.4%) with BHD and 42/48 (87.5%) with TDC showed improved clinical performance and radiological findings after surgery. Catheter failure was seen in 1/48 (2.4%) cases of TDC. Five patients (29.4%) in the BHD group and four patients (8.33%) in the TDC group underwent reoperations due to remaining hematomas, and they improved with a second operation, BHD or TDC. CONCLUSION: Both BHD at the maximal thickness area and TDC at the pre-coronal point are safe and effective drainage methods for symptomatic CSDHs with reasonable indications.

Manejo del hematoma subdural crónico mediante minitrépano y sistema de drenaje sin succión, experiencia en 213 pacientes / Management of chronic subdural hematoma with twist-drill craniostomy: report of 213 patients

Objetivos: Aún existen controversias respecto a la técnica en el manejo quirúrgico del hematoma subdural crónico. Este estudio tiene como objetivo describir nuestra experiencia en la craneostomía mediante el uso de minitrépano (twist drill). Pacientes y métodos: Fueron tratados 213 pacientes en los hospitales “Teodoro Maldonado Carbo” y “Alcívar” de Guayaquil, entre los meses de enero del 1992 y febrero del 2005. La técnica quirúrgica consistió en la evacuación del hematoma mediante minitrépano que se realizó en la cama del paciente y bajo anestesia local. Para evaluar los resultados utilizamos las escalas de Markwalder y la escala de evolución de Glasgow. Valoramos la evolución, las complicaciones y la recidiva. Resultados: Existió antecedente traumático en 65 % de los casos. Setenta y nueve por ciento ingresaron en grado 2 de la escala de Markwalder. Nueve por ciento presentó alguna complicación. Ocho por ciento recidivó, pero mostró curación después de un nuevo procedimiento. A los 6 meses, el 97 % evolucionó en grado 5 según la escala de evolución Glasgow. Conclusiones: La craneostomía por minitrépano es un método rápido, seguro, efectivo y menos costoso.

OBJECTIVES: Controversies regarding the surgical management of chronic subdural hematoma still remain. The objective of the present study was to describe our experience with twist-drill craniostomy. PATIENTS AND METHODS: Two hundred and thirteen patients were treated at the "Teodoro Maldonado Carbo" and "Alcívar" facilities between January 1992- February 2005. The surgical technique consisted of a twist-drill made under local anesthesia at the patient's bedside. We administered the Markwalder grading scale and the Glasgow outcome scale to assess treatment results. Clinical outcome, complications and relapse were measured. RESULTS: The etiology was traumatic in 65% of cases. At admission, 79% scored 2 of the Markwalder grading scale. Nine percent of the patients displayed complications. The chronic subdural hematoma persisted in 8%; they were treated again with another twist-drill craniostomy with favorable results. At six months, 97.6% reached 5 in the Glasgow outcome scale. CONCLUSIONS: Twist-drill craniostomy is a less time consuming, safe, effective, and cost-efficient method for the treatment of chronic subdural hematoma.

A Study On The Temperature Changes Of Bone Tissues During Implant Site Preparation / 대한치과보철학회지

The purpose of this study is to examine the possibility of thermal injury to bone tissues during an implant site preparation under the same condition as a typical clinical practice of Branemark implant system.All the burs for Branemark implant system were studied except the round bur.The experiments involved 880 drilling cases:50 cases for each of the 5 steps of NP, 5 steps of RP,and 7 steps of WP,all including srew tap,and 30 cases of 2mm twist drill. For precision drilling,a precision handpiece restraining system was developed(Eungyong Machinery Co.,Korea).The system kept the drill parallel to the drilling path and allowed horizontal adjustment of the drill with as little as 1 mu m increment.The thermocouple insertion hole.that is 0.9mm in diameter and 8mm in depth,was prepared 0.2mm away from the tapping bur,the last drilling step.The temperatures due to countersink,pilot drill,and other drills were measured at the surface of the bone,at the depths of 4mm and 8mm respectively. Countersink drilling temperature was measured by attaching the tip of a thermocouple at the rim of the countersink.To assure temperature measurement at the desired depths,''bent-thermocouples'' with their tips of 4 and 8mm bent at 120 were used.The profiles of temperature variation were recorded continuously at one second interval using a thermometer with memory function (Fluke Co.,U.S.A.)and 0.7mm thermocouples (Omega Co.,U.S.A.). To simulate typical clinical conditions,35mm square samples of bovine scapular bone were utilized.The samples were approximately 20mm thick with the cortical thickness on the drilling side ranging from 1 to 2mm.A sample was placed in a container of saline solution so that its lower half is submerged into the solution and the upper half exposed to the room air,which averaged 24.9 degrees C.The temperature of the saline solution was maintained at 36.5 degrees C using an electric heater (J.O Tech Co.,Korea).This experimental condition was similar to that ofa patient's opened mouth. The study revealed that a 2mm twist drill required greatest attention.As a guide drill, a twist drill is required to bore through a '' virgin bone,''rather than merely enlarging an already drilled hole as is the case with other drills.This typically generates greater amount of heat.Furthermore,one tends to apply a greater pressure to overcome drilling difficulty, thus producing even greater amount heat. 150 experiments were conducted for 2mm twist drill.For 140 cases,drill pressure of 750g was sufficient,and 10 cases required additional 500 or 100g of drilling pressure.In case of the former,3 of the 140 cases produced the temperature greater than 47 degrees C,the threshold temperature of degeneration of bone tissue (1983.Eriksson et al.5))which is also the reference temperature in this study.In each of the 10 cases requiring extra pressure,the temperature exceeded the reference temperature.More significantly,a surge of heat was observed in each of these cases.This observations led to addtional 20 drilling experiments on dense bones.For 10 of these cases,the pressure of 1,250g was applied.For the other 10,1,750g were applied.In each of these cases,it was also observed that the temperature rose abruptly far above the thresh-old temperature of 47 degrees C,sometimes even to 70 or 80 degrees C.It was also observed that the increased drilling pressure influenced the shortening of drilling time more than the rise of drilling temperature.This suggests the desirability of clinically reconsidering application of extra pressures to prevent possible injury to bone tissues. An analysis of these two extra pressure groups of 1,250g and 1,750g revealed that the t-statistics for reduced amount of drilling time due to extra pressure and increased peak temperature due to the same were 10.80 and 2.08 respectively suggesting that drilling time was more influenced than temperature. All the subsequent drillings after the drilling with a 2mm twist drill did not produce excessive heat, i.e.the heat generation is at the same or below the body temperature level. Some of screw tap,pilot,and countersink showed negative correlation coefficients between the generated heat and the drilling time,indicating the more the drilling time,the lower the temperature. The study also revealed that the drilling time was increased as a function of frequency of the use of the drill.Under the drilling pressure of 750g, it was revealed that the drilling time for an old twist drill that has already drilled 40 times was 4.5 times longer than a new drill. The measurement was taken for the first 10 drilings of a new drill and 10 drillings of an old drill that has already been used for 40 drillings. ''Test Statistics''of small samples t-test was 3.49,confirming that the used twist drills require longer drilling time than new ones.On the other hand,it was revealed that there was no significant difference in drilling temperature between the new drill and the old twist drill. Finally,the following conclusions were reached from this study: 1.Used drilling bur causes almost no change in drilling temperature but increase in drilling time through 50 drillings under the manufacturer-recommended cooling conditions and the drilling pressure of 750g. 2.The heat that is generated through drilling mattered only in the case of 2mm twist drills,the first drill to be used in bone drilling process;for all the other drills there is no significant problem. 3.If the drilling pressure is increased when a 2mm twist drill reaches a dense bone, the temperature rises abruptly even under the manufacturer-recommended cooling conditions. 4.Drilling heat was the highest at the final moment of the drilling process.