There is insufficient evidence to support a strong or moderate strength recommendation related to the extent of debridement in pTBI.

Conservative debridement involving less dissection of the brain is preferred over radical debridement as the latter approach is not associated with superior outcomes and risks greater injury to the brain.

No evidence or expert opinion supported distinct recommendations based on patient gender, age, wounding mechanism, or military vs. civilian context.

Cranial penetrating wounds are inherently contaminated and at a minimum require debridement and closure. The rationale for aggressive debridement is to decrease the incidence of intracranial infection, seizures, and other complications. However, more brain dissection may lead to increased morbidity and potentially mortality. The degree of neurosurgical debridement and removal of devitalized brain, bone fragments, and foreign bodies in pTBI has evolved over time. The modern definition of conservative debridement includes the removal of visible and easily accessible fragments of bone and foreign bodies that are encountered during the process of hematoma removal and hemostasis. In contrast, radical debridement involves an attempt to remove all devitalized brain and foreign materials including debridement of the entire missile tract though the use of image guidance (stereotactic navigation, ultrasound, or x-rays). This radical resection may also involve return to the operating room for further foreign body removal if retained lesions are present on postoperative imaging.

Initially neurosurgeons favored radical debridement believing it was necessary to reduce the risk of infection. Practice shifted, however, when multiple studies from the Vietnam war era demonstrated significant complications from aggressive debridement while conservative measures had relatively low incidence of infections (3-6% in the studies quoted in these previous guidelines).2,8,15,17 From the perspective of seizure prevention, bone fragment removal did not correlate with decreased seizure incidence, and although some studies showed that the presence of metallic fragments correlated with increased seizure risk, it was unclear if fragment removal decreased this risk.15,16

The first edition of these guidelines addressed the question of extent of debridement in detail. Unfortunately, as acknowledged by the authors, relevant studies were not rigorous limiting the conclusions that could be drawn. Based on this evidence, however, the authors recommended against aggressive removal of bone and foreign bodies for the purpose of preventing infections or seizures due to the increased risk of complications. The increased risk of infection was highly correlated with CSF leakage as will be addressed elsewhere in these guidelines.

No randomized trials or non-randomized cohort studies were identified that directly compared patient outcomes when treatment involved radical versus conservative debridement for penetrating brain injuries. Studies included in the last guideline (n=8) and additional case series (n=10) were identified in this new search that provide outcomes for patients who received either radical or conservative debridement.

Debridement type as reported in studies published across several years and locations was not standardized, and therefore no universal definition of radical and conservative debridement was used. To resolve this, we reviewed the description provided in several case series with a subgroup of members of the guideline panel and confirmed inclusions and assignments. For this summary, conservative is defined as debridement of the brain limited to fragments that can be seen and are easily accessible. No attempt is made to remove all or remote fragments or to follow the entire wound track. Using fingers or imaging to locate fragments was also considered radical. Standard of practice has shifted over time from favoring radical removal in an effort to prevent infections and potentially prevent seizures, to favoring conservative approaches to balance removing contaminants with causing further brain injury.

Case series were excluded in which either a) no information was provided about the approach to debridement or the information was not detailed enough to allow classification or b) the series included a mixture of cases that were treated with different approaches to debridement without reported outcomes separated by the debridement type.

Radical Debridement

We identified 11 articles that reported patient results when debridement was radical, including three reports from a large series that include overlapping cases from the Iran-Iraq War. Six of these case series report on military/war zone injuries and three examine civilian injuries.

The most recent military case series (Pilipenko, et al) reported 81 patients treated in Ukraine where as much bone and foreign matter as possible was removed from the brain using what the authors describe as a balanced approach that considers the fragment location and neurosurgical expert opinion.1 A study that followed U.S. soldiers injured in the Vietnam War (Carey, et al) reported outcomes from 103 patients who were treated under a policy in which all fragments were viewed as infectious and were removed. These patients may have had multiple surgeries to remove all traces of retained bone as well.2 The three articles by Aarabi, et al. included subsets of patients operated on during the Iran-Iraq War and examined different outcomes, reported different follow-up periods, and had different samples of patients,3-5. A series from the Korean War (Arendall et al.) included only injuries that included the air sinuses6 and involved radical debridement that removed bone and metallic fragments. A study in Lebanon (Haddad et al.) included 219 military and civilians injured and reported outcomes for the 164 who underwent thorough debridement.7 The earliest published study included is a large case series including 1,732 military and civilian patients treated in Vietnam with radical debridement.

These six military studies are similar in that a majority of injuries were caused by shrapnel or shell fragments while 10% to 35% were gunshot wounds. The mortality rates for four of the studies ranged from 11% to 16% (11.2%,8 11.7%,2 13.6%,1 16.3%3) with more extreme mortality values in two studies; 4.9% in the Korean War series that included a small number of cases of local debridement6 and 27.4% in the case series that included a mixed population treated in the Lebanese conflict.7 Two studies report that approximately three quarters of the patients (70.4%1 and 78.7%3) have good outcomes defined as a Glasgow Outcome Scale (GOS) score of 4 or 5. Four studies report infection rates ranging from 11%4 to 29%.6 Two studies include long term follow-up and reported that 32%5 and 23%6 of patients developed post traumatic epilepsy.

The radical debridement in civilian population series are all studies of gunshot wounds to the head. In a series of 37 patients in Slovenia, (Strojnik et al.) 70.3% (N=26) were treated with surgical debridement that aimed for complete removal of all fragments.9 A study in Brazil (Martins, et al.) included 151 gunshot victims10 all who were treated with radical debridement including patients with low Glasgow Coma Scale (GCS) scores as long as they did not have clinical evidence of brain stem comprise.10 In a study of 100 patient with gunshot wound in the United States (Grahm et al.), 43 were treated with surgical debridement that involved opening entrance and exit sites and following the bullet track.11

The civilian studies all had mortality rates that were similar (30.8%,9 37.9%,10 23%11) and generally higher than in the studies of military patients. The two studies that measured GOS reported relatively high levels of good recovery or moderate disability (34.6%9 and 53%10 of patients with GOS 5 or 4). The same types of infections were not reported across all three of these studies; however, the number of any kind of reported infection was small.

Conservative Debridement

We included seven studies of conservative debridement. These included six articles that report military or war zone patients; one in Syria (Jamous et al.),12 three in Turkey (Cosar, Gonul),13-15 and one group of patients in Lebanon described in two articles (Brandvold, Levi).16,17 One study (Miner, et al.) is a small case series of pediatric patients treated for gunshot wound in one urban medical center in the United States.18

The mortality rates were lower in the series from Turkey (7.75%,13 7.3%,14 and 8%15) than in the series from Syria (25%)12 and from Lebanon (26%).16,17 The infection rates were also low in the Turkish samples (rates for any infection of 5.5% with 9 abscess;13 3.8%;14 and 4.8%15 of the sample who developed cerebrospinal fluid [CSF] fistula who also developed central nervous system [CNS] infections), and higher in the series from the Lebanese conflict (11% developed CNS infection including 8% with meningitis).16 One series (Brandvold, et al.), reported that 22% of 43 patients who were available for long-term follow-up experienced post traumatic seizures.16 The one small study (N=33) of pediatric patients (Miner, et al.) reported a high rate of mortality (58%) with almost a third of patients (10 patients) dying in the emergency room or within 24 hours of injury.18 Six-month outcomes included good recovery for 6% (GOS 5), moderate disability for 27% (GOS 4) and severe disability for 9% (GOS 3).18 As these case series span over 30 years and include different environments and populations, caution should be exercised in making comparisons across these series. Each series report important outcomes including mortality, GOS, infection, or seizures, but these results can be attributed to many other factors that differ across the series other than the level of debridement.

Given this heterogeneity and the lack of direct comparison of radical and conservative debridement in any one study, we conclude that there is low strength of evidence that radical and conservative debridement results in similar outcomes in adult patients with penetrating brain trauma and that there is insufficient evidence to come to a separate conclusion about debridement in pediatric patients.

The extent of debridement has been extensively discussed and is an important subtopic in pTBI as it is based on the surgeon's clinical judgment. This characteristic makes studying this topic via trials challenging and results in a lack of relevant high-quality data. Thus, the current neurosurgical practice has developed from a variety of experiences reported in the literature.

Indeed, the treatment of penetrating head injury has evolved over time. Because of the unique incidence of pTBI in military conflicts, military-civilian translation has played a critical role in how debridement practices have evolved. The earlier studies from the Vietnam and Korean Wars advocated for aggressive debridement and removal of all foreign bodies including repeat operations for retained lesions with the goal of preventing infection and perhaps seizures as well. Ultimately concerns for increased morbidity and potentially mortality from the manipulation of viable tissue led to changes in practice. From the seizure perspective, the incidence is highly variable and only correlated with retained metallic foreign bodies. However, it remains unclear if removal would decrease the risk.

With more modern series, limited debridement was not associated with a higher risk for infection and did not increase mortality. These series included both conflict related injuries and peacetime pTBI. Evidence of benefit would be needed to justify surgery that is more injurious to the brain; as available evidence does not suggest such benefit, we provide a Level III recommendation to avoid aggressive removal of bone fragments and foreign bodies for the purpose of preventing infection and seizures.

There are limitations to the data. All of the cases are retrospective reviews with heterogenous patient populations. There are no studies directly comparing the two approaches, and the degree of debridement in each individual study is difficult to compare. It is important to consider that available literature focuses on metallic foreign bodies. Metal can have antibacterial properties and it is thus possible that there is greater need to aggressively remove other materials such as wood.

Our investigators feel that the contemporary approach of minimal debridement is the best current approach in pTBI and that dissection through brain to remove retained fragments should only be performed if infection develops at a deep fragment site. A more aggressive debridement may still be appropriate in some circumstances, such as with a highly contaminated wound. The role of antibiotics in preventing infection in the setting of retained fragments or contaminated wounds is not known with certainty and is discussed in another section of this guideline. Our investigators also feel that although the data presented here focuses on adult patients, there is no basis or rationale for considering a different approach in children.

While it would be important to study diverse penetrating brain injuries, rare injuries such as those involving non-metallic objects or low velocity pTBI would be more difficult to study. Under these circumstances, radical debridement may be appropriate, but given current practice, evidence would be required to support such a determination.