A Combination Procedure with Double C-Shaped ...

Clinical Study Received: July 9, 2010 Accepted after revision: February 7, 2011 Published online: April 20, 2011

Stereotact Funct Neurosurg 2011;89:178–184 DOI: 10.1159/000324903

A Combination Procedure with Double C-Shaped Skin Incision and Dual-Floor Burr Hole Method to Prevent Skin Erosion on the Scalp and Reduce Postoperative Skin Complications in Deep Brain Stimulation Young Seok Park a, b Jeong-Han Kang c Hae Yu Kim d Dong Wan Kang e Won Seok Chang a Joo Pyung Kim a Jin Woo Chang a

Department of Neurosurgery,a Severance Hospital, Brain Korea 21 Project for Medical Science, Brain Research Institute, Yonsei University College of Medicine, Seoul, b Bundang CHA Hospital, CHA University, Seongnam, c Kangdong Sacred Heart Hospital, Hallym University, Seoul, and d Haeundae Paik Hospital, Inje University, and e Pusan National University Hospital, Busan, Korea

Key Words Deep brain stimulation ⴢ Burr hole

Abstract Background: The purpose of this study was to introduce a combination procedure with double C-shaped skin incision and an adjusted dual-floor burr hole to prevent skin complications on the scalp with deep brain stimulation (DBS) surgery. Methods: Between March 2000 and March 2010, 504 DBS electrodes were implanted in 268 patients. We included both bilateral and unilateral DBS surgery cases for Parkinson’s disease, tremor, pain, obsessive-compulsive disorder and intractable seizure accompanied with cranial and IPG insertion procedure, but excluded motor cortex stimulation, and spinal cord stimulation. We used a straight skin incision in 118 patients, double C-shaped skin incision only in 113 patients since March 2006, and combined a double C-shaped skin incision and dual-floor burr hole in 37 patients since August 2009. We compared scalp wound complications and the height subscale of the Vancouver Scar Scale between previous straight or C-shaped skin incision and the combination procedure. Results: We had eight scalp erosions associated with infection (3.0%) and six disconnection (2.2%) cases among 268 pa-

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tients. Before the use of the double C- skin incision or adjusted dual-floor burr hole technique, we had 5 (4.2%) scalp erosion cases among 118 patients. With the introduction of the C-shaped incision, only 3 patients (2.7%) developed scalp erosion. However, no patient among 37 patients developed scalp erosion after using both double C-shaped skin incision and dual-floor burr hole technique. Scalp bump measured by the height subscale of the Vancouver Scar Scale was more cosmetic in the combination procedure. Conclusion: The combination procedure prevents skin complications associated with DBS surgery, with tensile strength, less impaired vascular supply and better cosmetic outcome. This promising approach prevents unwanted skin complications associated with DBS surgery and improves patient satisfaction. Copyright © 2011 S. Karger AG, Basel

Introduction

With the widespread use of deep brain stimulation (DBS) in the treatment of Parkinson’s disease, dystonia, essential tremor, and other psychiatric disorders, DBS offers an effective nonablative, reversible and adjustable therapy for movement disorders [1–3]. However, hardJin Woo Chang, MD, PhD Department of Neurosurgery, Yonsei University College of Medicine 134 Shinchon-Dong, Seodaemoon-Gu, Seoul 120-752 (Korea) Tel. +82 2 2228 2159, E-Mail jchang @ yuhs.ac

Color version available online

ware-related complications have been reported in up to 25.3% of the cases, limiting the therapeutic success of DBS [1, 3–6]. As with any implanted system, DBS introduces a new series of problems related to its hardware. Infection, malfunction and lead migration or fracture may increase patient morbidity and should be considered when evaluating the risk/benefit ratio of this therapy [7]. Although DBS is considered to be safer than lesion surgery [8], implantation of the indwelling electrode, connectors, and a generator can introduce a potential hardware-related adverse effect [9–13]. The skin erosions occur most commonly at the burr hole cap area, following the course of the cable to the IPG site [5]. The skin erosions are associated with an increased use of antibiotics and unnecessary hospital stays. Scalp bulging and possible scalp infection were the two main concerns with DBS surgery, especially in bald patients or when the burr hole is placed close to the hairline [14]. Thus, there is increased interest in preventing surgical complications around the scalp area with the DBS procedure. We present our promising results after a combination procedure with a double C-shaped skin incision and an adjusted dual-floor burr hole method described by Yamamoto et al. [14], which effectively reduced postoperative scalp skin erosion or infection.

Fig. 1. The double C-shaped incision provides more tensile

strength, less impaired vascular supply, and better cosmetic results than the straight incision. It separates the electrodes by more than 3 cm, thereby better protecting each system from being infected by the other.

Patients and Methods Patients Between March 2000 and March 2010, 504 DBS electrodes were implanted in 268 patients at the Severance Hospital, Korea. We performed DBS in 165 patients with Parkinson’s disease, 50 patients with dystonia, 38 with tremor, 5 patients with pain, 8 patients with obsessive-compulsive disorder, and 2 patients with intractable seizure. The straight incision was used in 118 patients in early series, the C-shaped skin incision only was used in 113 patients since March 2006, and both C-shaped skin incision and dual-floor burr hole technique were used in 37 patients since August 2009 by a single neurosurgeon (J.W.C.). We prospectively analyzed patients who received a double C or C-shaped incision and dual-floor burr hole at the Severance Hospital during a follow-up period of more than 6 months. The median age of patients was 55.1 years (range 18.0–80.0 years), and the median follow-up was 4.0 years (6–120 months). We compared scalp wound complications between the previous straight or C-shaped skin incision only and the combination procedure groups. All patients were prospectively followed up in an open-blinded fashion in the movement disorder clinic, and surgical complications that occurred during the follow-up period were recorded. We also compared the scalp ‘bump’ using a subscale of the Vancouver Scar scale (VSS) between the C-shaped skin incision only and the combination procedure groups [15]. One trained and experienced physician measured the scalp wound using VSS at the outpatient clinic. We compared scalp ‘bump’ only in Parkinson’s disease to escape selection bias.

Operative Technique We used sterile, transparent drapes to prevent infection and to communicate with patients. Electrode placement was performed under local anesthesia. Ceftriaxon 2.0 g was administered intravenously as a preoperative antibiotic within 30 min before the skin incision. We marked the entry point and skin incision on the skin area for the planned trajectory taking care not to make a big extended incision. An approximately 6- to 8-cm double C-shaped skin incision (Chang’s incision) was designed to avoid damage to the supratrochlear, supraorbicular, superficial temporalis and posterior auricular artery branches (fig. 1). After making the double Cshaped skin incision, skin clips were applied to prevent bleeding rather than vigorous coagulation of the scalp bleeding. Then, we made a 14-mm burr hole using a Midas Rex high speed pneumatic drill system (Medtronic, Inc., Fort Worth, Tex., USA) at the desired place. To avoid a scalp bump due to burr hole capping, the burr hole was adjusted using a 23-mm wide hand drill introduced by Yamamoto et al. [14] (fig. 2). We then inserted an O-shaped burr hole ring (Medtronic, Inc., Minneapolis, Minn., USA). The depth of the adjusted burr hole was 4–5 mm and the width was 23 mm. After mounting the O-shaped ring onto the adjusted burr, we attached the ring to the skull using a 5-mm screw to prevent loss of the O-shaped ring. The screw should be firmly fixed to secure the O-shaped ring. The author used a 5-mm-long self-tap-

Surgical Technique for DBS Surgery

Stereotact Funct Neurosurg 2011;89:178–184

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a

b

c

d

Fig. 2. a A 1-mm burr hole using a Midas Rex high speed pneumatic drill system (Medtronic, Inc., Fort Worth, Tex., USA) at the target place on the left. After this procedure, a 23-mm adjusted dual-floor burr hole using a hand drill introduced on the right as described by Yamamoto et al. [14]. b After mounting an O-shaped ring on the adjusted burr, we fixed the ring to the skull using a 5-mm screw to firmly secure the O-shaped ring. c An adjusted

180


burr hole created using the dual-floor burr hole method can decrease the pressure on the skin and prevent protrusion of the burr hole cap and electrode. d Scalp bulging, especially in bald patients or when the burr hole is placed close to the hairline, on the left. The dual-floor burr hole with better cosmetic result is shown on the right.

Park/Kang/Kim/Kang/Chang/Kim/ Chang

Table 1. Clinical characteristics of the 8 patients who had scalp wound complications after DBS surgery

Patient No.

Age/sex Diagnosis Site

Pathogen

Follow-up months

Event Treatment months

1 2 3 4 5 6 7 8

61/M 41/M 62/M 61/M 66/F 67/M 67/F 49/M

MRCNS MRSA no growth MRSA MRSA pseudomonas MRSA MRCNS

72 60 60 13 37 36 72 72

1 2 4 1 40 36 1 12

PD PD PD PD PD PD PD PD

scalp scalp scalp scalp, IPG scalp, connector, IPG scalp scalp scalp

removal removal I&D only removal removal removal removal I&D only

I&D = Irrigation and drainage; IPG = implantable pulse generator; MRSA = methicillin-resistant Staphylococcus aureus; MRCNS = methicillin-resistant coagulase-negative staphylococci; PD = Parkinson’s disease.

ping screw. After the dura mater was incised in a cruciate fashion, a cortical incision was made to introduce the stimulation electrode. To avoid unnecessary cerebrospinal fluid (CSF) leakage, we attached the dura mater to the pia mater using a bipolar coagulation at three or four points. After inserting the simulation electrode using the microelectrode recording (MER) technique, we used a cottonoid and glue to prevent CSF leakage. We then attached the burr hole capping to the ‘O’ ring without moving the stimulation electrodes. The proximal electrodes were coiled in a unilateral direction to avoid interlocking or protruding of the scalp. We did not use externalized electrodes for continuous test stimulation. To prevent posterior scalp erosion at the connector site, the connector should be securely placed in the deep subcutaneous tissue. On the same day, we implanted a pulse generator (IPG), Soletra 7426 (Medtronic, Inc., Minneapolis, Minn., USA) on the pectoralis fascia, and the IPG was sutured to the fascia with a 2-0 silk suture on the subclavicular area. Statistical Analysis Continuous variables were described by median and range values. We compared the two groups using Fisher’s exact test for categorical data and the independent samples t test for continuous data. Statistical significance was assumed at p ! 0.05. Statistical analysis was carried out with the Social Science statistical software, version 12.0 (SPSS, Chicago, Ill., USA).

Table 2. Skin incision and adjusted double dual-floor burr hole

affecting skin complication Surgical methods Skin incision Straight C-shaped Burr hole Usual Adjusted burra Straight incision C-shaped incision only Combination procedureb

Number of Scalp p value* patients complication 118 150

5 (4.2%) 3 (2.0%)

0.306

231 37 118 113 37

8 (3.5%) 0 (0.0%) 5 (4.2%) 3 (2.7%) 0 (0.0%)

0.182

* p value using Fisher’s exact test. a Adjusted burr hole was made using dual-floor burr hole methods. b Combination procedure means C-shaped skin incision and dual-floor burr hole methods performed simultaneously.

We performed 268 DBS surgeries between March 2000 and March 2009. The patients’ median age was 55.1 years (range 18.0–80.0 years), and the median follow-up was 4.0 years (6–120 months). During this period, there were 8 cases (3.0%) with scalp erosions. All of these cases were patients with Parkinson’s disease. We had 8 cases of scalp erosion associated with infection (3.0%) (table 1). Among 118 patients who underwent conventional straight skin

incision without dual-floor burr hole, 5 (4.2%) developed scalp erosion. Among the group of patients who underwent the C-shaped skin incision, 3 (2.7%) developed scalp erosion. However, none of the 37 patients who underwent the combination procedure developed scalp erosion. Three (2.7%) among the 113 patients with C-shaped skin incisions developed scalp wound complications. However, we had no skin complications in 37 patients who underwent the combination procedure. Among all the patients, six disconnections (2.2%) were observed during the follow-up period (table 2). There were no statistically significant differences between the conventional straight incision and the C-shaped



Results

181


b a

Fig. 3. To prevent posterior scalp erosion at the connector site, the connector should be secured deep in the subcutaneous tissues. a In a 66-year-old female, the distal extension exposed at the posterior scalp near the mastoid area was exposed. b The connector should be at least 4 cm away from the mastoid area to escape the relatively thin skin coverage area.

incision. Also, there was no significant difference between the straight incision and the combination procedures. However, scalp erosion did not occur when the C-shaped skin incision was combined with the dual-floor burr hole technique. Cosmetically, patient satisfaction, particularly among bald patients, was higher with the combination procedure because it did not cause scalp bumping on the forehead (fig. 2d). The subscale of pigmentation, vascularity and pliability of the VSS was the same in the C-shaped skin incision only and combination procedures. However, the height subscale of VSS was significantly decreased in the combination procedure (table 3).

Discussion

We showed promising results associated with scalp erosion using a double C-shaped skin incision combined with the adjusted dual-floor burr hole method. The combination procedure decreased skin complications in the scalp area, and also increased patient satisfaction with respect to cosmetic results. Skin erosion with or without infection at the burr hole cap area frequently occurs with DBS surgery. It is possible 182


that a straight scalp incision instead of curvilinear incision more frequently causes infection [7]. Some surgeons favor a single linear skin incision parallel over the coronal suture, because it has advantages in surgical time. However, if infection occurs in one of the two systems, it may affect the other electrode. The double C-shaped incisions are spaced more than 3 cm apart, thus protecting each system from being infected by the other. Also, the approach provides a better blood supply and prevents any damage to the normal blood supply to the scalp. The double C-shaped skin incision has more tensile strength than the straight skin incision. It provides more space than a straight incision for handling the positioning of the coiling electrodes and for securing and suturing connectors in the deep subcutaneous tissue. We found that this novel skin incision method gives more strength and causes less skin complications than the conventional straight incision. Since the burr-hole ring and cap method was first introduced in 1981 [16], it has provided an easier and more stable way to hold electrodes in position compared to microplate fixation. However, the technique causes the skin to bulge about 3–4 mm after rubber capping the burr hole ring. The adjusted dual-floor burr hole method of using a burr hole ring and cap is very effective for preventing Park/Kang/Kim/Kang/Chang/Kim/ Chang

Table 3. Comparing scalp wound healing status of patients who

bulging of the scalp [14]. The combination procedure practically eliminated scalp erosions, and provided better cosmetic results. Instead of burr hole capping, some authors have used a miniplate to secure and fix the electrodes [17, 18]. However, the use of a miniplate can crush the electrode. Adjusting the burr hole may require extra time and effort. We used a 23-mm perforator, which was introduced by Yamamoto et al. [14]. This perforator is very effective and optimal in adjusting the burr hole. We have shown that the dual-floor burr hole is effective in preventing infection-associated scalp erosion. Furthermore, the use of a dual-floor burr hole increased patient satisfaction and decreased skin complications. Bulky hardware connector should be securely placed into the deep subcutaneous tissue at least 4 cm away from the mastoid area (fig. 3). Lead fracture was reported in up to 42% of patients when the in-line extension is placed in the neck area [19]. Schwalb et al. [19] recommend connecting DBS electrodes to the in-line extension in the parietal subgalea instead of the neck to avoid erosion and cosmesis. We had eight skin erosion cases at the burr hole cap area with Parkinson’s disease. It remains to be investigated whether the skin of PD patients is more vulnerable than that of patients with non-neurodegenerative disease and is therefore associated with a high risk for skin complications after DBS [5]. We did not use externalized elec-

trodes for the test. Some authors advocated that externalized electrodes for continuous test stimulation did not have any significant impact on skin complications [5]. Other reports which used externalized electrodes showed an increased infection rate [7]. The period of the stimulation trial using externalized electrodes was associated with an increased infection rate [7]. The causative organisms that are most often implicated in DBS hardware infections were Staphylococcus (S. epidermidis and S. aureus), Enterobacter, Streptococcus, Pseudomonas and rarely Mycobacterium or Candida [12, 20, 21]. Miller et al. [22] reported that antibiotics for wound irrigation or local antibiotics before skin closing administered intravenously can reduce postoperative infection in ventriculoperitoneal shunt. This could ignite the development of antibiotic-impregnated DBS. However, some argue that even the antibiotic-impregnated system does not significantly reduce infection [23]. Skin erosion could occur in other areas such as the connector site and the IPG pocket area. Placing a low profile connector such as model 7482 (Medtronic Inc., Minneapolis, Minn., USA) into the bone grooves may help reduce skin erosion [24]. To prevent skin erosion in the IPG pocket area, the pocket should be adequate not to form a seroma after surgery, and IPG should be placed on or underneath the well-vascularized pectoralis fascia rather than into the subcutaneous fat. Burdick et al. [25] reported twiddler syndrome as the cause of DBS hardware failure. Suturing IPG to the facia or clavicular bone would be helpful for securing IPG. There were some limitations in our study. We did not find the combination procedure had a statistically significant effect on the prevention of skin complications. If adding more patients over time in this study, it might yield statistically significant results. Moreover, this study was not a double-blinded open-label study, and there was a different follow-up period with each procedure. That means that the longer the follow-up period, the more likely will the number of complications increase. Also, the learning curve might have affected our results. Despite such limitations, our approach showed promising results in preventing scalp complications. None of the patients who received the combination procedure had scalp erosion. Although scalp wound complications can occur long after surgery, the perioperative infection rates most likely represent around 1.5–4.5% within 6 months of surgery [5, 26]. While we used the latest surgical technique in this study, we had some limitation in prospectively comparing the two surgical methods. Despite such limitations, our study is highly practical for the neurosurgeon.



underwent bilateral STN DBS for Parkinson’s disease using the Vancouver Scar Scale

Age, years Sex, F/M Follow-up, months Heightb 0 1 2 3

C-shaped incision only (n = 22)

Combination procedure (n = 17)a

p value

61.8 (49–69) 13/9 62.0 (14–64) 1.4180.50 0 13 9 0

60.4 (46–72) 8/9 8.6 (6–12) 0.080.0 17 0 0 0

0.901 0.528