Accepted Manuscript Analysis of factors contributing to infections following cranioplasty: a single-institution retrospective chart review Margaret A. Riordan, MD, Venita M. Simpson, MD, Walter A. Hall, MD MBA PII:
S1878-8750(15)01683-6
DOI:
10.1016/j.wneu.2015.11.070
Reference:
WNEU 3476
To appear in:
World Neurosurgery
Received Date: 15 October 2015 Revised Date:
18 November 2015
Accepted Date: 19 November 2015
Please cite this article as: Riordan MA, Simpson VM, Hall WA, Analysis of factors contributing to infections following cranioplasty: a single-institution retrospective chart review, World Neurosurgery (2016), doi: 10.1016/j.wneu.2015.11.070. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
ACCEPTED MANUSCRIPT
Analysis of factors contributing to infections following cranioplasty: a single-institution retrospective chart review
RI PT
Margaret A Riordan MD, Venita M Simpson MD, and Walter A Hall MD MBA Department of Neurosurgery SUNY-Upstate Medical University Syracuse, NY United States Keywords: cranioplasty, decompressive craniectomy, immunosuppression, post-operative infection
SC
Running Title: Cranioplasty infections
Contact Information
EP
Present Address: 300 Pasteur Dr. Stanford, CA 94305-5327 [email protected] 650-725-0701 fax: 650-723-2815
TE D
Corresponding Author: Margaret Riordan, MD 605 Jacobsen Hall 175 Elizabeth Blackwell Street Syracuse, NY 13210
M AN U
Abbreviations List: CSF- cerebrospinal fluid, PEEK- polyether ether ketone, PMMApolymethyl methacrylate, MRSA- methicillin resistant staphylococcus aureus
AC C
Alternative Author: Walter Hall, MD MBA 605 Jacobsen Hall 175 Elizabeth Blackwell Street Syracuse, NY 13210 [email protected] 315-464-5511 fax: 315-464-6384
ACCEPTED MANUSCRIPT
Introduction Decompressive craniectomy is an effective method for treating refractory intracranial hypertension.1-4
RI PT
Following this procedure, patients must undergo further surgery to replace their bone flap. Cranioplasty is required for protection against further trauma, cosmesis, and improvement of neurological function; however, this operation is associated with a higher complication rate than many other neurosurgical procedures.4-8 Historically, the
replacement material has been the original cryopreserved or subcutaneously stored autologous bone flap, but
currently, the use of various flaps fabricated from synthetic materials with similar tensile strength has become more
SC
prevelant.6,9-14
Infectious complications following cranioplasty increase morbidity, require long-term antibiotic therapy, and require subsequent surgeries to remove the infected bone flap and eventually replace the flap, all of which lead
M AN U
to higher health care costs. During the period of time in which the patient has a cranial defect, they are exposed to many co-morbidities including lack of protection from trauma, syndrome of the trephined, infections at the surgical site, and psychosocial factors from living with an obvious cranial defect; thus, it is important to determine why cranioplasty infections occur to minimize the interval without a bone flap and to prevent the need for subsequent surgeries.15
The aim of this retrospective chart review was to analyze which patient characteristics and surgical factors
Methods Data Collection
TE D
increase the infection rate following cranioplasty.
A single center retrospective chart review of 262 patients who underwent cranioplasty procedures at
EP
SUNY-Upstate Medical University, a level one trauma center, between 2001 and 2013 was performed. Patients were excluded from the study if any of the surgeries were performed at another hospital or if they had a cranioplasty for a reason other than for filling a large cranial defect; thus, data from a total of 186 patients was analyzed.
AC C
Patient characteristics extracted from the medical records included age, gender, and co-morbidities resulting in an immunocompromised state, prior wound infection, and history of multiple same site procedures. Patients were considered to be immunocompromised if they suffered from an autoimmune disorder, were taking immunomodulating therapies, being treated with chemotherapy or radiation therapy, or recently hospitalized for an unrelated infection.
Surgical information including reason for cranioplasty, cranioplasty material, interval between craniectomy
and cranioplasty, and cranioplasty size were documented. The choice of cranioplasty flap material, time to cranioplasty after initial decompression or removal for infection was based on the preference of the attending surgeon. The cranial defect was measured on scout images obtained during CT reconstructions to calculate the
ACCEPTED MANUSCRIPT
cranioplasty area. If a patient had bilateral cranioplasties, the sum of the two areas was used as the total cranioplasty size. A large cranioplasty was considered to be greater than 10,000 mm2. Bone flaps were handled and stored according to the SUNY-Upstate peri-operative services manual policy number OPER B-01. Briefly, once the cranial flap is removed, it is soaked in bacitracin solution on the sterile operative field. Immediately at the conclusion of the case, the flap is scrubbed with bacitracin solution and any
RI PT
periosteum, soft tissue, and blood is removed. A culture swab is taken and sent to microbiology for aerobic and anaerobic culture. The flap is then engraved with the patient’s initials and medical record number, wrapped in polypropylene sterilization wrap, placed in a sterilization peel pack with indicator strip and autoclaved at 135 degrees for four minutes with a 30 minute dry time. The flap is then stored in a temperature monitored area.
The type of synthetic material was abstracted from the operative report. In some cases, the specific type of
SC
synthetic material was not mentioned; thus, these were categorized as “other synthetic.” Synthetic cranioplasty flaps were generated using each individual company’s protocol then subsequently autoclaved and double packaged in sterile packing with the exception of the titanium mesh cranioplasties. Sterile titanium mesh was cut to the size of
M AN U
the defect intra-operatively.
All patients received peri-operative antibiotics. Post-operative complications that included presence of a fluid collection, wound dehiscence, and infection development were recorded. The overall number of infections, infectious organism, time to infection and time to cranial flap re-implantation were noted. The aim of this study was to determine if any specific surgical or patient factors increased the chance of infection following cranioplasty.
TE D
Data Analysis
Statistical analysis was done using SPSS Version 17 (IBM Corporation, Armonk NY, USA). A two tailed T test was used to determine significance. A p-value less than 0.05 was considered statistically significant. When calculating significance relating to specific subgroups, patients were excluded from analysis if data regarding a specific parameter was not documented in their electronic medical record; thus, not all subgroups include the entire
Results
EP
study population.
AC C
186 patients underwent cranioplasty at SUNY-Upstate Medical University between 2001 and 2013. 115
(62%) patients were male and 71 (38%) female and the average age was 35.7 years (Table One). The most common reason for cranioplasty was decompressive craniectomy following trauma in 92 patients (49%), following aneurysmal subarachnoid hemorrhage (aSAH) in 23 (12.4%), following an infection in 11 (5.9%) and following spontaneous intracranial hemorrhage in 10 (5.4%). Thirty-eight patients (20%) had a cranioplasty following removal of an infected bone flap and four (2.1%) following tumor resection. Other reasons for cranioplasty included penetrating injury (2 patients), evacuation of subdural empyemas (2 patients), removal of a vascular malformation (2 patients), evacuation of a subdural hematoma (one patient), and a large cranial vault remodeling (one patient) (see Figure One). Various synthetic materials comprised the most common material used for cranioplasty and
ACCEPTED MANUSCRIPT
autologous bone stored via cryopreservation was used in 48 patients (25.8%) (Table Two). The average time to cranioplasty was 7.34 months (range 1-40 months) and the average cranioplasty flap size was 12,265 mm2. The overall infection rate in this study was 24% (45 out of 186 flaps) and the average time to infection was 6.5 months (range
S1878-8750(15)01683-6
DOI:
10.1016/j.wneu.2015.11.070
Reference:
WNEU 3476
To appear in:
World Neurosurgery
Received Date: 15 October 2015 Revised Date:
18 November 2015
Accepted Date: 19 November 2015
Please cite this article as: Riordan MA, Simpson VM, Hall WA, Analysis of factors contributing to infections following cranioplasty: a single-institution retrospective chart review, World Neurosurgery (2016), doi: 10.1016/j.wneu.2015.11.070. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
ACCEPTED MANUSCRIPT
Analysis of factors contributing to infections following cranioplasty: a single-institution retrospective chart review
RI PT
Margaret A Riordan MD, Venita M Simpson MD, and Walter A Hall MD MBA Department of Neurosurgery SUNY-Upstate Medical University Syracuse, NY United States Keywords: cranioplasty, decompressive craniectomy, immunosuppression, post-operative infection
SC
Running Title: Cranioplasty infections
Contact Information
EP
Present Address: 300 Pasteur Dr. Stanford, CA 94305-5327 [email protected] 650-725-0701 fax: 650-723-2815
TE D
Corresponding Author: Margaret Riordan, MD 605 Jacobsen Hall 175 Elizabeth Blackwell Street Syracuse, NY 13210
M AN U
Abbreviations List: CSF- cerebrospinal fluid, PEEK- polyether ether ketone, PMMApolymethyl methacrylate, MRSA- methicillin resistant staphylococcus aureus
AC C
Alternative Author: Walter Hall, MD MBA 605 Jacobsen Hall 175 Elizabeth Blackwell Street Syracuse, NY 13210 [email protected] 315-464-5511 fax: 315-464-6384
ACCEPTED MANUSCRIPT
Introduction Decompressive craniectomy is an effective method for treating refractory intracranial hypertension.1-4
RI PT
Following this procedure, patients must undergo further surgery to replace their bone flap. Cranioplasty is required for protection against further trauma, cosmesis, and improvement of neurological function; however, this operation is associated with a higher complication rate than many other neurosurgical procedures.4-8 Historically, the
replacement material has been the original cryopreserved or subcutaneously stored autologous bone flap, but
currently, the use of various flaps fabricated from synthetic materials with similar tensile strength has become more
SC
prevelant.6,9-14
Infectious complications following cranioplasty increase morbidity, require long-term antibiotic therapy, and require subsequent surgeries to remove the infected bone flap and eventually replace the flap, all of which lead
M AN U
to higher health care costs. During the period of time in which the patient has a cranial defect, they are exposed to many co-morbidities including lack of protection from trauma, syndrome of the trephined, infections at the surgical site, and psychosocial factors from living with an obvious cranial defect; thus, it is important to determine why cranioplasty infections occur to minimize the interval without a bone flap and to prevent the need for subsequent surgeries.15
The aim of this retrospective chart review was to analyze which patient characteristics and surgical factors
Methods Data Collection
TE D
increase the infection rate following cranioplasty.
A single center retrospective chart review of 262 patients who underwent cranioplasty procedures at
EP
SUNY-Upstate Medical University, a level one trauma center, between 2001 and 2013 was performed. Patients were excluded from the study if any of the surgeries were performed at another hospital or if they had a cranioplasty for a reason other than for filling a large cranial defect; thus, data from a total of 186 patients was analyzed.
AC C
Patient characteristics extracted from the medical records included age, gender, and co-morbidities resulting in an immunocompromised state, prior wound infection, and history of multiple same site procedures. Patients were considered to be immunocompromised if they suffered from an autoimmune disorder, were taking immunomodulating therapies, being treated with chemotherapy or radiation therapy, or recently hospitalized for an unrelated infection.
Surgical information including reason for cranioplasty, cranioplasty material, interval between craniectomy
and cranioplasty, and cranioplasty size were documented. The choice of cranioplasty flap material, time to cranioplasty after initial decompression or removal for infection was based on the preference of the attending surgeon. The cranial defect was measured on scout images obtained during CT reconstructions to calculate the
ACCEPTED MANUSCRIPT
cranioplasty area. If a patient had bilateral cranioplasties, the sum of the two areas was used as the total cranioplasty size. A large cranioplasty was considered to be greater than 10,000 mm2. Bone flaps were handled and stored according to the SUNY-Upstate peri-operative services manual policy number OPER B-01. Briefly, once the cranial flap is removed, it is soaked in bacitracin solution on the sterile operative field. Immediately at the conclusion of the case, the flap is scrubbed with bacitracin solution and any
RI PT
periosteum, soft tissue, and blood is removed. A culture swab is taken and sent to microbiology for aerobic and anaerobic culture. The flap is then engraved with the patient’s initials and medical record number, wrapped in polypropylene sterilization wrap, placed in a sterilization peel pack with indicator strip and autoclaved at 135 degrees for four minutes with a 30 minute dry time. The flap is then stored in a temperature monitored area.
The type of synthetic material was abstracted from the operative report. In some cases, the specific type of
SC
synthetic material was not mentioned; thus, these were categorized as “other synthetic.” Synthetic cranioplasty flaps were generated using each individual company’s protocol then subsequently autoclaved and double packaged in sterile packing with the exception of the titanium mesh cranioplasties. Sterile titanium mesh was cut to the size of
M AN U
the defect intra-operatively.
All patients received peri-operative antibiotics. Post-operative complications that included presence of a fluid collection, wound dehiscence, and infection development were recorded. The overall number of infections, infectious organism, time to infection and time to cranial flap re-implantation were noted. The aim of this study was to determine if any specific surgical or patient factors increased the chance of infection following cranioplasty.
TE D
Data Analysis
Statistical analysis was done using SPSS Version 17 (IBM Corporation, Armonk NY, USA). A two tailed T test was used to determine significance. A p-value less than 0.05 was considered statistically significant. When calculating significance relating to specific subgroups, patients were excluded from analysis if data regarding a specific parameter was not documented in their electronic medical record; thus, not all subgroups include the entire
Results
EP
study population.
AC C
186 patients underwent cranioplasty at SUNY-Upstate Medical University between 2001 and 2013. 115
(62%) patients were male and 71 (38%) female and the average age was 35.7 years (Table One). The most common reason for cranioplasty was decompressive craniectomy following trauma in 92 patients (49%), following aneurysmal subarachnoid hemorrhage (aSAH) in 23 (12.4%), following an infection in 11 (5.9%) and following spontaneous intracranial hemorrhage in 10 (5.4%). Thirty-eight patients (20%) had a cranioplasty following removal of an infected bone flap and four (2.1%) following tumor resection. Other reasons for cranioplasty included penetrating injury (2 patients), evacuation of subdural empyemas (2 patients), removal of a vascular malformation (2 patients), evacuation of a subdural hematoma (one patient), and a large cranial vault remodeling (one patient) (see Figure One). Various synthetic materials comprised the most common material used for cranioplasty and
ACCEPTED MANUSCRIPT
autologous bone stored via cryopreservation was used in 48 patients (25.8%) (Table Two). The average time to cranioplasty was 7.34 months (range 1-40 months) and the average cranioplasty flap size was 12,265 mm2. The overall infection rate in this study was 24% (45 out of 186 flaps) and the average time to infection was 6.5 months (range
