Disabling spasticity has been managed in a variety

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1 J Neurosurg Pediatrics 10: , 2012 Evaluation of salvage techniques for infected baclofen pumps in pediatric patients with cerebral palsy Clinical article Sydney M. Hester, M.D., 1 John F. Fisher, M.D., 2 Mark R. Lee, M.D., Ph.D., 3 Samuel Macomson, M.D., 1 and John R. Vender, M.D. 1 Department of 1 Neurosurgery and 2 Section of Infectious Diseases, Medical College of Georgia, Georgia Health Sciences University, Augusta, Georgia; and 3 Pediatric Surgical Subspecialists, Dell Children s Medical Center of Central Texas, Austin, Texas Object. Intrathecal baclofen therapy has been used successfully for intractable spasticity in children with cerebral palsy. Infections are rare, but they are potentially life threatening if complicated by bacteremia or meningitis. Treatment without removal of the system is desirable if it can be done safely and effectively. Methods. The authors reviewed the records of 207 patients ranging from 3 to 18 years of age with cerebral palsy who underwent placement or revision of a baclofen pump. They identified 38 patients with suspected or documented infectious complications. Initial attempts were made to eradicate infection with the devices in situ in all patients. Methods and effectiveness of pump salvage were evaluated. Results. Of the 38 patients identified, 13 (34.2%) had documented infections; 11 had deep wound/pocket empyemas and 2 had meningitis. Eight patients with deep wound infections received intravenous antibiotics alone. All required pump explantation. The remaining 3 patients underwent a washout procedure as well; the infection was cured in 1 patient. Both patients with meningitis received intravenous and intrathecal antibiotics, and both required device explantation. In addition, 25 patients (65.8%) had excessive or increasing wound erythema. No objective criteria to document a superficial infection were present. The wounds were considered suspicious and were managed with serial examinations and oral antibiotics. The erythema resolved in 24 of the 25 patients. Conclusions. In general, observation, wound care, and oral antibiotics are sufficient for wounds that are suspicious for superficial infection. For deep-seated infection, antibiotic therapy alone is generally insufficient and explantation is required. Washout procedures can be considered, but failures are common. ( Key Words device-related infection salvage therapy pediatric neurosurgery baclofen pump cerebral palsy functional neurosurgery Abbreviation used in this paper: ITB = intrathecal baclofen. Disabling spasticity has been managed in a variety of ways. Oral therapy with baclofen has been the traditional form of management but is not universally effective, and some patients with spasticity do not respond to its effects despite escalating doses. In other patients, tolerance to the medication or undesirable side effects preclude its use. For several decades, ITB therapy has been used with success for intractable spasticity. 1 3,10,11,20,22 24 The rationale for this method of treatment has been to concentrate the drug at the target site for maximal therapeutic effect while minimizing systemic drug levels and side effects. In addition, with available delivery systems, therapy is reversible and titratable. Complex delivery strategies tailored to unique patient requirements are also possible. Pump implantation requires an invasive procedure, but this approach to therapy is typically safe and effective. However, mechanical malfunctions occur in up to 25.8%, and 16.7% of procedures are complicated by infection. 13,29 Mechanical complications can involve catheter tubing, pump, or the hub connector itself. 7,8,17,30 Infection of the pump, surrounding tissue, catheter, or meninges is potentially life threatening. Current therapeutic options for infected delivery systems include immediate explantation or attempts at pump salvage in less acute circumstances. Because many patients with severe spasticity rely heavily on their therapy, 548 J Neurosurg: Pediatrics / Volume 10 / December 2012

2 Salvage techniques for infected baclofen pump in cerebral palsy pump salvage is desirable if the infection can be effectively treated with the device in situ. However, attempts to sterilize infected medical devices have generally required prolonged antibiotic therapy, and progression of infection or involvement of the nervous system can result in increased morbidity or even death. 9 A better understanding of the likelihood of success for device salvage therapy is required to determine if the risk to the patient and the cost and inconvenience of prolonged antibiotics and wound washout procedures can be justified. Accordingly, we evaluated this therapy in 38 pediatric patients with cerebral palsy whose implantable devices were complicated by infection or considered to be at high risk for infection. Our retrospective report details the salvage methods used and their effectiveness. Methods Patient Selection We conducted a retrospective review of all patients younger than 18 years of age who had infectious complications related to baclofen infusion systems. Through a systematic chart review we identified a total of 38 (18.4%) of 207 patients whose devices became infected (13 patients [34.2%]) or were considered suspicious and potentially at risk for infection (25 [65.8%]). The cohort presented represents an 8-year experience with the most recent patients treated now 12 months without signs of infection. This study was approved by the Georgia Health Sciences University Institutional Review Board. Infection Diagnostic criteria for infection included the following: signs and symptoms consistent with infection (fever, chills, headache, malaise, nausea, vomiting, increasing wound tenderness, and signs of erythema, induration, ulcer, drainage, wound dehiscence, or abscess at the pump site) or a positive Gram stain or culture obtained from pus, a deep wound, or device components. Laboratory studies included white blood cell counts and erythrocyte sedimentation rate. Infections were considered to be deep wound infections when the pump, pocket, tubing, or CSF was involved. Patients who were considered at risk for infection were noted to have excessive, progressive erythema extending more than 1 cm from their incision line, with or without wound tenderness, at their routine postoperative visit in the absence of any other signs or symptoms listed as consistent with infection. Pump Salvage Successful salvage of the ITB system was defined as a 3-month minimum interval from termination of treatment without the development of signs or symptoms of infection. All dehiscent or draining wounds were cultured at the draining site. Intraoperative cultures were obtained in all cases in which surgical debridement or explantation was required. In the remaining patients, antibiotics were selected to provide coverage for gram-positive organisms. Specific salvage techniques were based on the type of infection encountered. J Neurosurg: Pediatrics / Volume 10 / December 2012 Deep Wound Infection. For deep wound infection in the absence of meningitis and pocket empyema, intravenous antibiotics for 2 weeks followed by oral antibiotic therapy for 1 2 weeks was first attempted. Wound Infection With Meningitis. In cases of wound infection with meningitis, a combination of intravenous and intrapump antibiotics was used. In these cases, there was no evidence clinically or radiographically of pocket empyema. Antibiotics were continued for a minimum of 2 weeks or until negative CSF samples were obtained. Pocket Empyema. In the presence of purulent material within the pump pocket, significant tissue deterioration, or wound dehiscence, a washout and reimplantation technique was selected. In cases in which washout was performed, the pump pocket pump incision was opened in the operating room, and the pump and pocket contents were copiously irrigated. Devitalized tissue was debrided from the pocket and skin edges. Cultures and Gram stains were obtained from any drainage in the area. The pump was exposed and removed from the pocket, which was then irrigated with bacitracin and saline for 25 minutes. Explantation. Antibiotic therapy was considered unsuccessful, and explantation was recommended when the wound continued to deteriorate, a dehiscence developed, or there was a failure to clear the infection after an adequate course of antibiotics. Patients undergoing explantation were started on oral baclofen prior to explanation to minimize withdrawal and were maintained on oral medication until reimplantation. One patient s caregiver opted against new pump placement. Removal of the implant was followed by wound debridement, revision of wound margins, and closure over a drain. The patients were given an average of 2 weeks of intravenous antibiotics tailored to the pathogen(s) identified or suspected. For seriously ill or severely immunocompromised patients with extensive local evidence of deep wound infection, urgent pump explantation was the preferred treatment. Superficial Infection. For suspected superficial infections, a course of oral antibiotics averaging days followed by observation was undertaken. Oral antibiotics were selected to provide coverage for suspected grampositive bacterial infection. Results The cases of 2 patients with wound complications requiring immediate explantation of the pump were not included in this report. Clinical data for the 13 patients with documented infection are listed in Table 1. Oral antibiotic therapy was associated with resolution of the erythema in 24 of the 25 patients with suspected superficial infections. The remaining patient s incision developed a superficial dehiscence and required intravenous antibiotic therapy. This ultimately healed without incident. Eight of the 11 patients with deeper wound infections were treated with intravenous antibiotics alone. All required pump removal. The 3 other patients within that group underwent washout procedures followed by administration of intravenous antibiotics. In only 1 of these patients was treatment success- 549

3 S. M. Hester et al. TABLE 1: Characteristics in 13 patients with cerebral palsy who experienced deep wound infection, meningitis, or empyema* Case No Age (yrs), Sex Weight (kg) Type of Infection Isolate Therapy Outcome 1 3, F 12 pocket empyema group B streptococci washout, vancomycin ip & iv (7 days), iv ampicillin (7 days), discharged home on Keflex po (10 days) 2 9, F 16 pocket empyema MSSA washout, vancomycin ip & iv (10 days) 3 16, M 29 pocket empyema MSSA washout, vancomycin ip, nafcillin iv (4 days) explant 4 11, F 28 pocket infection complicated by meningitis P. aeruginosa ceftazidime iv, gentamicin iv (5 days) explant 5 15, M 22 pocket empyema MSSA ceftazidime iv (30 min prior to incision) explant 6 10, F 22 pocket empyema MRSA, Acinetobacter vancomycin iv (2 days) explant 7 9, M 13 pocket empyema MSSA vancomycin iv, ceftriaxone iv (7 days) explant 8 14, M 42 pocket empyema P. aeruginosa ceftazidime iv (7 days) explant 9 15, M 51 pocket empyema no growth cefazolin iv (10 days) explant 10 10, M 26 pocket infection complicated by meningitis P. aeruginosa tobramycin iv, ciprofloxacin po (3 wks) explant 11 6, F 15.5 deep wound infection MSSA vancomycin iv (2 days) explant 12 4, M 12 pocket empyema P. aeruginosa ceftazidime iv, tobramycin iv (3 days) explant 13 3, M 13.6 pocket empyema S. epidermidis vancomycin iv (8 days) explant salvage * explant = explantation; ip = intrapump; iv = intravenous; MSSA = methicillin-sensitive S. aureus; po = by mouth. The pump was removed at the request of the caregiver. 550 J Neurosurg: Pediatrics / Volume 10 / December 2012

4 Salvage techniques for infected baclofen pump in cerebral palsy ful. The 2 patients who developed meningitis were given both intravenous and intrathecal antibiotics. The latter drugs were delivered through the pump using the dosing described by Zed et al. 34 Nevertheless, both patients ultimately required explantation of the pump. All organisms isolated were susceptible to the antimicrobial agents chosen, but this did not influence outcome. Of the 12 patients whose pumps were explanted, 11 have remained infection free for at least 12 months after antibiotics were discontinued. The remaining patient whose pump was removed (Case 12) developed a CSF leak, which was closed and treated with a longer course of outpatient intravenous antibiotics. This patient has also remained infection free for more than 12 months. Discussion With the steadily increasing use of ITB therapy, more infections are being encountered. Hence, interest in various strategies for pump salvage has also continued to grow. Several investigators have reported successful management of infections without explantation in adults. 6,9,15,22,26,34 The majority of the patients described in these series were infected with low-virulence organisms. In contrast to many of our patients, most of the successes were in adult patients with normal body habitus and without marked physical deformities (Table 2). There is no information available to evaluate pump salvage modalities in children. For a patient with cerebral palsy, the benefits of an attempted salvage of the ITB system are theoretically very compelling. Patients are typically very dependent on ITB therapy, and interruption in drug delivery can have significant side effects. Also, most patients have significantly limited soft-tissue reserves due to their compromised body habitus, which is not amenable to multiple surgical procedures. Modifications in implant technique, such as subfascial pump placement 18 and multilayered wound closure, can enhance the success rate in dealing with a superficial infection by adding additional layers of vascularized tissue over the implant and reducing tension on the skin incision. Suspected Infection Our experience in 24 of 25 patients indicates that an attempt can be made to manage early, suspected superficial infections with oral antibiotics and careful followup. With success, the ITB system can remain in situ. A mitigating factor in the group of patients with suspected superficial wound infection is the lack of direct evidence of actual infection. Tissue reaction to the incision and indwelling suture varies among patients, and, in this case, inflammation cannot always be distinguished from early infection. Thus, although it is likely that the erythema was related to early infection in at least some of these patients, it is not clear if the administration of a short course of oral antibiotics caused or merely coincided with the resolution of the erythema noted in this group of patients. In either case, there was no evidence that the administration of this course of antibiotic therapy had any adverse effect on wound healing. Careful monitoring is essential for success and was evident in the patient with mild wound dehiscence. Immediate administration of intravenous antibiotics and aggressive topical wound care prevented progression to a deeper infection and led to the ultimate salvage of the pump. Deep Infection, Meningitis, or Pocket Empyema Our experience does not support the general effectiveness of antibiotic therapy (intravenous with or without intrapump delivery) for deep infection, meningitis, or TABLE 2: Successful salvage procedures of ITB pumps reported in the literature* Authors & Year No. of Patients Age (yrs), Sex Disease Isolate Management Boviatsis et al., , F autoimmune myelitis S. aureus iv ceftriaxone, iv vancomycin, oral rifampin; pump washout 27, M 5-yr Hx SCI S. epidermidis iv & intrapocket vancomycin; oral rifampin 26, F cerebral palsy P. aeruginosa iv & intrapump amikacin; oral ciprofloxacin Zed et al., , M degenerative motor S. epidermidis ip & iv vancomycin, oral rifampin neuron disorder Galloway & Falope, , M multiple sclerosis P. aeruginosa ip gentamicin Bennett et al., , M cerebral palsy** S. epidermidis iv & ip vancomycin, oral rifampicin, iv flucloxacillin Penn, NR NR Pseudomonas ip gentamicin paucimobilis Samuel et al., , M multiple sclerosis S. aureus iv flucloxacillin, iv ficidin, ip gentamicin * Hx = history of; NR = not reported; SCI = spinal cord injury. The antibiotic management was in addition to the pump disinfection and therapeutic aspirations. This patient had only been spastic requiring ITB since 17 years of age. In addition to vancomycin, baclofen was coadministered. Comorbidity of congenital ichthyosis persistently colonized with Pseudomonas. ** Spasticity requiring ITB at 18 years of age. J Neurosurg: Pediatrics / Volume 10 / December

5 S. M. Hester et al. pocket empyema in patients with cerebral palsy. The low likelihood of pump salvage in most patients, the problems attendant to prolonged intravenous antibiotic therapy, and risk of disease progression must be carefully weighed before any patient can be considered a candidate for this approach. Consistent with most published experience, our patient with a deep wound infection did not respond to antibiotic therapy alone. The virulence of the causative organism, methicillin-resistant Staphylococcus aureus, was a likely factor in the therapeutic failure. This patient was also at the 3rd percentile for growth, but the relationship of growth retardation to the refractory nature of this infection remains speculative. As is the case with other types of medical devices (for example, spinal or cranial) infections caused by staphylococci of lower virulence such as Staphylococcus epidermidis and other coagulase-negative staphylococci may be more amenable to pump salvage. 16,28,31,33 Zed et al. 34 and Boviatsis et al. 9 identified 2 adults who were both infected by S. epidermidis and whose ITB systems were successfully salvaged. The infection in one of these patients was complicated by meningitis that was managed successfully with intrapump and intravenous antibiotics. Similarly, Bennett and colleagues 6 successfully treated an 18-yearold boy with cerebral palsy who developed meningitis after his ITB system became infected by S. epidermidis. A cure was accomplished without explantation using a continuous intrapump infusion of vancomycin (50 mg/ml) at 5 mg daily followed by oral rifampin and intravenous flucloxacillin. In our patient whose ITB pump was successfully salvaged, the causative organism was Streptococcus agalactiae (group B streptococci). In addition to a pump washout with bacitracin/gentamicin/saline, intravenous vancomycin (selected based on organism sensitivities) was given for 7 days. Although S. agalactiae was cultured from the device, the pump cavity contained only serous fluid rather than grossly purulent material. Therefore, another reason for cure in this individual may have been the early identification and treatment of the infection. It is noteworthy that the patient s weight was within the normal range for her age, suggesting that her nutritional status and body habitus were also normal. In both of our patients with infection complicated by meningitis, the causative organism was Pseudomonas aeruginosa. The difficulty of eradicating this glycocalyxproducing gram-negative bacillus from medically approved devices (such as soft contact lenses) and its virulence are well known. 14,35 Major advances have been made in the therapy of P. aeruginosa infections. Many potent antipseudomonal agents are now available, including antipseudomonal penicillins, extended spectrum cephalosporins, aminoglycosides, new beta-lactam agents, such as monobactams and carbapenems, and fluoroquinolones. Appropriate use of these agents has resulted in response rates in the range of 70% 75%, even in neutropenic patients with Pseudomonas infections. 25 Penetration into the CSF of available antipseudomonal agents, particularly when supplemented by intrathecal infusion, should be reasonably effective. 25 Notwithstanding isolated reports of successful treatment of meningitis complicating ITB pump infections without explantation, we believe immediate removal is indicated in children with cerebral palsy until more data are available. Occasionally baclofen vials themselves may become contaminated and result in pump infection. Penn 22 described such a common source outbreak in 4 adult patients who developed infections due to Pseudomonas paucimobilis (currently known as Sphingomonas paucimobilis), a common environmental contaminant, but a rare cause of human infection. 5 The organism was isolated from the vials containing the baclofen that had been used for infusion. None of the patients had clinical signs of infection, and the pumps were sterilized in situ with gentamicin. Galloway and Falope 15 described the fortuitous isolation of P. aeruginosa from the routine follow-up cultures of the ITB device of an adult patient with congenital ichthyosis. The source was likely the patient s skin, which had been persistently colonized with this organism, although the authors did not provide proof. Nevertheless, this device was also successfully sterilized in situ with instillation of gentamicin. Mitigating Factors There are many potential reasons why infected pumps may be difficult to salvage in children with cerebral palsy. It is well known that impaired nutritional status, often seen in this population, adversely affects both the innate and adaptive immune systems of humans and unequivocally retards wound healing. 21,32 Patients are often at high risk for bacterial colonization, particularly in the urine, as well as transient bacteremia due to breakdown of the skin. General hygiene is often very challenging, particularly in the most compromised patients, and further increases the risk of infection particularly in patients with underlying suboptimal immune function. Body habitus and tissue health and volume are also major factors in wound healing after the implantation of a large device. It is common for patients with cerebral palsy to have a low weight for age. 19 Our patients were no exception; almost half were below the 3rd percentile, and none were above the 30th percentile for their age on a sex-specific growth chart. Washout procedures using antibiotic solutions in conjunction with both local and systemic antibiotic therapy tailored to the causative organism can be successful in the treatment of infections involving ITB implants. However, an aggressive approach with early intervention and careful selection of patients who can be safely considered for management with the device in situ is required. Patients with infections caused by more virulent or difficult-totreat organisms such as S. aureus, hemolytic streptococci, enterococci, gram-negative bacilli, and fungi should be excluded from consideration. Adequate tissue must remain after debridement of the wound sufficient to accommodate a large foreign body. Irrigation of the pocket and the external surfaces of the ITB delivery system after debridement have been used successfully by other investigators in some patients, 9 but we were unable to find controlled studies of this form of local treatment. Such trials are needed to adequately assess the risks of catheter damage and to determine whether there is uniform distribution of antimicrobial solutions. The development and utility of closed irrigation systems for the continuous 552 J Neurosurg: Pediatrics / Volume 10 / December 2012

6 Salvage techniques for infected baclofen pump in cerebral palsy local delivery of antibiotic and irrigation fluid is another approach to these infections that needs to be explored. 4 As the popularity of and indications for vacuum-assisted wound closure continue to increase, studies addressing the adaptability of this technique to ITB infections would also be of interest. 3,12,27,28 Conclusions Intrathecal baclofen pump infections will continue to be a problem for medical and surgical specialists as the use of this technology continues to increase. In general, local wound care and appropriate oral antibiotics and close follow-up are sufficient for suspected or superficial infections involving the baclofen pump site. However, the patient s growth and development, nutritional status, and virulence of the infecting organism may suggest otherwise and should be carefully assessed. Since close observation is critical to therapeutic success and patient safety, poor patient compliance or suboptimal caregiver support are absolute contraindications to a salvage strategy. In deep-seated infection, antibiotic therapy alone is generally insufficient and explantation is required. A washout procedure can be considered in an unusual circumstance, but failures are common. Solutions to the problems associated with implantable ITB devices have not kept pace with technological advances in these delivery systems and are a fertile area for future research. Disclosure The authors report no conflict of interest concerning the materials or methods used in this study or the findings specified in this paper. Author contributions to the study and manuscript preparation include the following. Conception and design: Vender, Hester, Fisher. Acquisition of data: all authors. Analysis and interpretation of data: all authors. Drafting the article: Vender, Hester, Macomson. Critically revising the article: all authors. Reviewed submitted version of manuscript: all authors. Approved the final version of the manuscript on behalf of all authors: Vender. Administrative/ technical/material support: Vender, Fisher, Lee. Study supervision: Vender. References 1. Albright AL, Barry MJ, Painter MJ, Shultz B: Infusion of intrathecal baclofen for generalized dystonia in cerebral palsy. J Neurosurg 88:73 76, Albright AL, Gilmartin R, Swift D, Krach LE, Ivanhoe CB, McLaughlin JF: Long-term intrathecal baclofen therapy for severe spasticity of cerebral origin. J Neurosurg 98: , Albright AL, Turner M, Pattisapu JV: Best-practice surgical techniques for intrathecal baclofen therapy. J Neurosurg 104 (4 Suppl): , Anderson LD, Horn LG: Irrigation-suction technic in the treatment of acute hematogenous osteomyelitis, chronic osteomyelitis, and acute and chronic joint infections. 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7 S. M. Hester et al. 27. Vallet C, Saucy F, Haller C, Meier P, Rafoul W, Corpataux JM: Vacuum-assisted conservative treatment for the management and salvage of exposed prosthetic hemodialysis access. Eur J Vasc Endovasc Surg 28: , Vender JR, Hester S, Houle PJ, Choudhri HF, Rekito A, McDonnell DE: The use of closed-suction irrigation systems to manage spinal infections. J Neurosurg Spine 3: , Vender JR, Hester S, Waller JL, Rekito A, Lee MR: Iden tification and management of intrathecal baclofen pump complications: a comparison of pediatric and adult patients. J Neurosurg 104 (1 Suppl):9 15, Ward A, Hayden S, Dexter M, Scheinberg A: Continuous intrathecal baclofen for children with spasticity and/or dystonia: Goal attainment and complications associated with treatment. J Paediatr Child Health 45: , Wenger DR, Mubarak SJ, Leach J: Managing complications of posterior spinal instrumentation and fusion. Clin Orthop Relat Res 284:24 33, Worley CA: Why won t this wound heal? Factors affecting wound repair. Dermatol Nurs 16: , Yuan-Innes MJ, Temple CL, Lacey MS: Vacuum-assisted wound closure: a new approach to spinal wounds with exposed hardware. Spine (Phila Pa 1976) 26:E30 E33, Zed PJ, Stiver HG, Devonshire V, Jewesson PJ, Marra F: Continuous intrathecal pump infusion of baclofen with antibiotic drugs for treatment of pump-associated meningitis. Case report. J Neurosurg 92: , Zhu H, Thuruthyil SJ, Willcox MD: Determination of quorum-sensing signal molecules and virulence factors of Pseudomonas aeruginosa isolates from contact lens-induced microbial keratitis. J Med Microbiol 51: , 2002 Manuscript submitted March 1, Accepted September 6, Please include this information when citing this paper: published online October 5, 2012; DOI: / PEDS Address correspondence to: John R. Vender, M.D., Department of Neurosurgery, Medical College of Georgia, BI 3088, th Street, Augusta, Georgia jvender@georgia health.edu. 554 J Neurosurg: Pediatrics / Volume 10 / December 2012