Management of pediatric renal trauma - Results from the American Association for Surgery and Trauma Multi-Institutional Pediatric Acute Renal Trauma Study (Mi-PARTS).

BACKGROUND: Pediatric renal trauma is rare and lacks sufficient population-specific data to generate evidence-based management guidelines. A non-operative approach is preferred and has been shown to be safe. However, bleeding risk assessment and management of collecting system injury is not well understood. We introduce the Multi-institutional Pediatric Acute Renal Trauma Study (Mi-PARTS), a retrospective cohort study designed to address these questions. This manuscript describes the demographics and contemporary management of pediatric renal trauma at Level I trauma centers in the United States. METHODS: Retrospective data were collected at 13 participating Level I trauma centers on pediatric patients presenting with renal trauma between 2010-2019. Data were gathered on demographics, injury characteristics, management, and short-term outcomes. Descriptive statistics were used to report on demographics, acute management and outcomes. RESULTS: In total 1216 cases were included in this study. 67.2% were male, and 93.8% had a blunt injury mechanism. 29.3% had isolated renal injuries. 65.6% were high-grade (AAST Grade III-V) injuries. The mean Injury Severity Score (ISS) was 20.5. Most patients were managed non-operatively (86.4%) 3.9% had an open surgical intervention, including 2.7% having nephrectomy. Angioembolization was performed in 0.9%. Collecting system intervention was performed in 7.9%. Overall mortality was 3.3% and was only observed in polytrauma. The rate of avoidable transfer was 28.2%. CONCLUSION: The management and outcomes of pediatric renal trauma lacks data to inform evidence-based guidelines. Non-operative management of bleeding following renal injury is a well-established practice. Intervention for renal trauma is rare. Our findings reinforce differences from the adult population, and highlights opportunities for further investigation. With data made available through Mi-PARTS we aim to answer pediatric specific questions, including a pediatric-specific bleeding risk nomogram, and better understanding indications for interventions for collecting system injuries. LEVEL OF EVIDENCE: IV, Epidemiological (prognostic/epidemiological, therapeutic/care management, diagnostic test/criteria, economic/value-based evaluations, and Systematic Review and Meta-Analysis).

Are pediatric surgery fellowship websites ready for the changing paradigms in the virtual interview era?

Purpose: With the COVID-19 pandemic, in-person fellowship interviews were curtailed, leading candidates to seek information from other resources. Our main purposes were (1) to determine what information recent participants in the match needed to evaluate programs and (2) to assess which of these were available online. Methods: A focus group of ten recent graduates/applicants identified information that was important in choosing a fellowship program. In August 2020 and December 2021, websites belonging to the American Pediatric Surgical Association (APSA) and individual programs were assessed. Results: Recent applicants identified 55 pieces of information considered important to their decision making. Of 57 pediatric surgery fellowships, 98% were listed on APSA's website. Program descriptions on APSA's website listed on average 60% of program information desired by applicants. All listed fellowship director, accreditation status, faculty list, and current fellow(s). Other descriptors frequently noted were alumni (95%), graduate's board performance (83%), ECMO exposure (77%), and curriculum (70%). Information desired but less frequently available were fellow case logs (63%), trauma center designation (53%), burn center designation (40%), research opportunities (30%), candidate interview assistance (25%), and supplemental fellowships (12%). There were 7% of program descriptions that were not updated for at least a year. Conclusions: APSA and individual program websites were complimentary. Websites often lacked data that applicants sought to inform their rank list. To best adapt to the evolving virtual interview paradigm, we suggest reporting key information on a central APSA website with more nuanced information available via links to program specific websites. Supplementary Information: The online version contains supplementary material available at 10.1007/s44186-023-00104-w.

Case report: Duplicated appendicitis with history of cloacal exstrophy causing bowel obstruction.

INTRODUCTION: Cloacal and bladder exstrophy are rare embryological defects that can cause developmental disruption of surrounding organ structures, the pelvis, spinal cord, and small intestines being the most commonly affected. Duplicated appendix is another rare embryological defect that has historically caused confusing clinical presentations. Our case highlights a rare instance of a patient with cloacal exstrophy who presented with a bowel obstruction and an associated inflamed duplicated appendix. CASE PRESENTATION: A newborn male is born with omphalocele-exstrophy-imperforate anus-spinal defects (OEIS) complex. As primary surgical reconstruction was pursued, the patient was found to have a non-inflamed duplicated appendix, which was left unremoved. In the following months, the patient experienced episodes of small bowel obstruction, eventually requiring surgical intervention. During this operation, the duplicated appendix was noted to be inflamed, prompting removal of both appendices. DISCUSSION: This case highlights the increased prevalence of duplicated appendix in a patient with cloacal exstrophy, as well as the utility of prophylactic appendectomy for patients incidentally found to have a duplicated appendix intraoperatively. The duplicated appendix may lead to increased rates of complications and atypical presentation of appendicitis, supporting the practice of prophylactic appendectomy in patients with an incidentally found duplicated appendix. CONCLUSION: We suggest clinicians be aware of the association and potentially atypical presentation of appendicitis in patients with a duplicated appendix, particularly in the setting of cloacal exstrophy. The decision to prophylactically remove an incidentally found, non-inflamed duplicated appendix may be beneficial in preventing confusing clinical presentations and future complications.

Establishment of a successful robotic pediatric general surgery practice.

Robotic-assisted surgery (RAS) has a variety of theoretical advantages, including tremor filtration, optimal visualization, and improvement of surgeon ergonomics. Though it has achieved wide application in pediatric urology, the majority of pediatric general surgeons do not employ RAS. This study reports our institution's experience with RAS on a pediatric general surgery team. Following IRB approval, a retrospective review of all pediatric patients at our academic children's hospital who underwent RAS between 2017 and 2022 for pediatric general surgical conditions was performed. Patient demographics, operation performed, operating time, complications, and recovery were evaluated. A total of 159 children underwent RAS, increasing from 10 patients in 2017 to 59 patients in 2022. The median age and weight were 15.3 years and 76.4 kg, and 121 (76.1%) were female. The application of RAS was successful in all cases. There were no intraoperative complications and no conversions to an open approach. Eleven patients (6.9%) had unplanned presentations to the emergency department within 30 days. Five of these patients (3.1%) required admission to the hospital. This study demonstrates that the application of RAS in an academic pediatric general surgery practice is feasible and safe. The application of RAS to pediatric general surgery should continue to increase as operative teams increase their experience and comfort.Level of evidence Level IV.

The Current Pediatric Surgery Job Market: A Perspective of Recent Fellowship Graduates.

PURPOSE: This study describes the job market from the perspective of recent pediatric surgery graduates. METHODS: An anonymous survey was circulated to the 137 pediatric surgeons who graduated from fellowships 2019-2021. RESULTS: The survey response rate was 49%. The majority of respondents were women (52%), Caucasian (72%), and had a median student debt burden of $225,000. Considering job opportunities, respondents strongly emphasized camaraderie (93%), mentorship (93%), case mix (85%), geography (67%), faculty reputation (62%), spousal employment (57%), compensation (51%), and call frequency (45%). 30% were satisfied with the employment opportunities available, and 21% felt strongly prepared to negotiate for their first job. All respondents were able to secure a job. Most jobs were university-based (70%) or hospital employed (18%) positions where surgeons covered median of two hospitals. 49% wanted protected research time, and 12% of respondents were able to secure substantial, protected research time. The median compensation for university-based jobs was $12,583 below the median AAMC benchmark for assistant professors for the corresponding year of graduation. CONCLUSION: These data highlight the ongoing need for assessment of the pediatric surgery workforce and for professional societies and training programs to further assist graduating fellows in preparing to negotiate their first job. TYPE OF STUDY: Survey LEVEL OF EVIDENCE: Level V.

Short-term outcomes of thoracoscopic versus open lobectomy for congenital lung malformations.

PURPOSE: Thoracoscopic and open approaches for the management of congenital lung malformations (CLM) has been debated. The aim of this study is to compare 30-day outcomes for non-emergent lobectomies in children. METHODS: The National Surgical Quality Improvement Program-Pediatric database was queried for patients undergoing CLM resection from 2013 to 2020. Outcomes were compared by operative technique in an intention-to-treat model and then propensity matched. RESULTS: 2157 patients met inclusion criteria and underwent non-emergent pulmonary lobectomy for CLM. The intended operative approach was thoracoscopic in 57.7% of patients. Patients in the open group compared to the thoracoscopic were more likely to be born premature, have chronic lung disease, require preoperative oxygen support, and be ventilator dependent. After propensity matching, there was no statistically significant difference in 30-day mortality, unplanned readmission, and other complications between the thoracoscopic and open groups. Thoracoscopic approach was associated with a shorter length of stay. The proportion of cases approached via thoracoscopy increased over time from 48.8% in 2013 to 69.9% in 2020. CONCLUSIONS: This large multicenter retrospective matched analysis demonstrates thoracoscopic lobectomy in children has similar favorable 30-day outcomes and shorter length of stay for the non-emergent management of CLM, compared to open thoracotomy. LEVEL OF EVIDENCE: Level III.

Optimal Timing of Inguinal Hernia Repair in Premature Infants: A NSQIP-P Study.

INTRODUCTION: Among premature infants, the incidence of inguinal hernias is reported to be as high as 30%. Despite being one of the most commonly performed procedures, the optimal setting of inguinal hernia repair (IHR) that is inpatient versus outpatient remains debatable. We sought to compare the 30-day outcomes of each approach by querying the National Surgical Quality Improvement Program-Pediatric database. MATERIALS AND METHODS: A retrospective cohort study comparing inpatient versus outpatient IHR using the National Surgical Quality Improvement Program-Pediatric database from 2013 to 2019 was performed. Demographic and clinical data were initially compared using univariate analysis. Continuous variables are presented as median and interquartile range and categorical variables are presented as n (%). Subsequently, cohorts were propensity matched using clinically and statistically significant patient characteristics. RESULTS: 928 patients underwent IHR, 634 (68.3%) while inpatient, 294 (31.7%) following hospital discharge. Inpatient IHR was associated with lower age at the time of surgery (120 versus 147 d; P < 0.0001), younger gestational age (27 versus 33 wk; P < 0.0001), decreased probability of repair in elective setting (87.2% versus 97.3%; P < 0.0001), and increased preoperative supplemental oxygen need (42% versus 4.4%; P < 0.0001). Comparison of propensity matched cohorts revealed that inpatient IHR was associated with increased procedure time (82 versus 51 min; P < 0.0001) and anesthetic duration (146 versus 102 min; P < 0.0001), wound infection rates (3.8% versus 0%; P = 0.007), blood transfusions (4.2% versus 0.5%; P = 0.036), unplanned intubations (2.8% versus 0%; P = 0.03), ventilator days (0 versus 0; range [0,30 versus 0,2]; P = 0.002), reoperation rate (5.6% versus 0%; P < 0.001), postoperative hospital length of stay (4 versus 1 d; P < 0.0001), and unplanned readmissions (8.9% versus 0.9%; P = 0.002). CONCLUSIONS: Inpatient IHR in premature neonates were associated with different postoperative outcomes than outpatient IHR. At least in the elective setting among premature infants, outpatient IHR can be considered safe in select patients while we await higher quality prospective data.

Prenatal administration of heparin-binding epidermal growth factor-like growth factor in an experimental model of necrotizing enterocolitis decreased both incidence and severity of the disease.

Background: Necrotizing enterocolitis (NEC) is the leading gastrointestinal cause of death in premature infants and causes long-term disabilities. Previously, enteral heparin-binding epidermal growth factor-like growth factor (HB-EGF) administered after birth demonstrated decreased incidence and severity of NEC in a neonatal animal model of NEC. We investigated the potential prophylactic strategy of preventing NEC using prenatally administered HB-EGF. Methods: An HB-EGF (800 µg/kg/dose) dose was injected into pregnant rats via tail vein or intraperitoneal route 2 hours prior to delivery. After cesarean section (C-section) at 21 days' gestation, the rat pups were subjected to the NEC protocol by inducing stressors: hypoxia, hypothermia, hypertonic feeds, and orogastric gavage of lipopolysaccharide (2 mg/kg). Postnatally, pups were monitored for 96 hours and assessed for the development of clinical and postmortem histological NEC. Results: The experimental NEC incidence in untreated, stressed rat pups was 66%. Compared with untreated pups, the maternal administration of HB-EGF correlated with a significant NEC incidence and severity decrease in rat pups. The strongest decrease was seen when HB-EGF was administered via the intraperitoneal route 2 hours prior to C-section (66% vs 31%, *p<0.05). Prenatal HB-EGF administration significantly increased pups' survival after NEC protocol exposure, with the greatest benefit observed in the group that received HB-EGF intraperitoneally 2 hours before delivery. Conclusions: Prenatal administration of HB-EGF decreases the incidence and severity of NEC, preserves gut barrier function and increases survival. This may represent a novel prophylactic clinical strategy for NEC offered to mothers at risk of delivering a premature infant.

An Unusual Case of Primary Ileal Trichobezoar Causing Intussusception.

BACKGROUND Intussusception, which is the prolapse of one section of intestine into another, is a common cause of small-bowel obstruction in pediatric patients. Bezoars are concretions of ingested foreign material. Trichobezoars, which are bezoars made of hair, occur in the context of trichotillomania, the compulsive pulling of hair, and trichophagia, the eating of hair. If gastric trichobezoars grow to sufficient size, an intestinal extension can serve as a lead point for intussusception to occur. Rarely, hair passes completely through the stomach and forms a trichobezoar within the small bowel. This obstruction can also create lead points and cause intussusception. This is one of the few reported cases of intussusception due to a primary intestinal bezoar. CASE REPORT We present the case of an 8-year-old boy with an unknown history of trichophagia and a preliminary diagnosis of appendicitis. Upon imaging, a bowel obstruction related to a small-bowel intussusception was discovered to be the probable cause. A diagnostic laparoscopy revealed an ileo-ileal intussusception caused by an ileal bezoar. Conversion to exploratory laparotomy assisted in removing the causative bezoar. The patient recovered without postoperative complications. CONCLUSIONS We report a case of an isolated intestinal trichobezoar causing intussusception in a boy. While intussusception secondary to a trichobezoar most commonly occurs due to 'Rapunzel syndrome,' this case shows that it is possible for an intestinal trichobezoar to form without the presence of 'Rapunzel syndrome.' This unique cause of intussusception presented as a small-bowel obstruction, requiring evacuation of the bezoar.

Objective Personality Determination: A Useful Addition to the Traditional Process of Pediatric Surgical Fellow Selection.

BACKGROUND: Selection of pediatric surgical trainees is a multifaceted process heavily influenced by in-person interviews to determine personality makeup and institutional compatibility. We present our experience in utilizing a validated personality inventory in the selection of our candidates. METHODS: All applicants selected for an in-person interview for the 2020 Pediatric Surgery Match were offered the Big Five Inventory (BFI) questionnaire. An initial rank order list (ROL) was formulated employing application information and in-person interview score. A reformulated ROL was created after incorporating BFI data. Correlation of specific personality characteristics vs position on the ROL was assessed for both the initial ROL and the reformulated ROL. RESULTS: Thirty-four applicants were interviewed and 24 (70.6%) were ranked. Linear regression analysis identified a lower neuroticism score directly related to a higher position on the initial ROL {R = .4626, P = .023}. The reformulated ROL identified a higher conscientiousness score {R = .5331; P = .007} and a lower neuroticism score {R = -.4383; P = .032} correlated with ascending the final ROL. CONCLUSIONS: The self-administered BFI adds objectivity to personality determination gleamed from the standard face-to-face interview. Conscientiousness and neuroticism had a significant impact on the final ROL position. Adding objective personality data appears to provide additional aid in this difficult process.

Large mesenteric cyst mimicking an ovarian cyst in an 8-year-old: A case report.

INTRODUCTION AND IMPORTANCE: Pediatric mesenteric cysts, rare and usually benign intra-abdominal tumors, are a difficult preoperative diagnosis due to ambiguous clinical characteristics. The final diagnosis is typically established only during surgery or histological analysis. CASE PRESENTATION: An 8-year-old female presented with five days of worsening abdominal pain, associated with nausea, vomiting, and fever, as well as vague tenderness in the right quadrants on examination. Computed tomography imaging showed a 10.5 × 8.7 × 7 cm abdominal mass, most suspicious for a cystic mass of ovarian origin. Upon diagnostic laparoscopy, a mesenteric cyst extending to the root of the mesentery was visualized and entirely resected after conversion to an exploratory laparotomy. Histopathological examination of both the cystic fluid and specimen suggest a benign mesenteric cyst. CLINICAL DISCUSSION: Although mesenteric cysts are noticeably rare, it is important differential to consider in pediatric patients with non-specific symptoms like abdominal pain and distention, intestinal obstruction, or a palpable abdominal mass. Notably, these cysts can be managed successfully by complete surgical resection with an excellent outcome. CONCLUSION: This report recounts an interesting case of a large mesenteric cyst that mimicked an ovarian cyst in a pre-pubertal girl.

Thoracoscopic segmentectomy for a large previously undiagnosed CPAM presenting as a spontaneous pneumothorax: A case report.

INTRODUCTION: Incidentally found congenital pulmonary airway malformations (CPAM) in older children are extremely rare and have traditionally been managed with minimally invasive versus open lobectomy of the affected lobe. PRESENTATION OF CASE: In this report, we present a 11-year-old male who presented with a recurrent spontaneous pneumothorax and was found to have a large symptomatic CPAM confined to a single segment of the right lower lobe. The patient was successfully treated with thoracoscopic segmentectomy without any residual disease seen on follow up imaging. DISCUSSION: Minimally invasive thoracoscopic approach has many advantages over open approach including better pain control, reduced hospital length of stay, and decreased intraoperative blood loss. With increasing use of minimally invasive approaches, lung-sparing surgery has demonstrated to be a viable and an attractive option for definitive resection of CPAM, without compromising resection margins and/or future lung function. CONCLUSION: This report demonstrates that minimally invasive lung-sparing surgical treatment of a large CPAM is feasible in older children.

The Utility of Gallbladder Absence on Ultrasound for Children With Biliary Atresia.

Background: Biliary Atresia (BA) is congenital condition, where infant intra- and extrahepatic bile ducts become obliterated, leading to cholestasis, and cirrhosis if untreated. This study aims to assess the predictive measure of absent gallbladder on ultrasounds (US) performed in infants with cholestasis for diagnosing BA. Method: After Institutional Review Board approval, retrospective chart reviews of 61 infants with cholestasis found 43 (70.5%) were diagnosed with BA. A pediatric radiologist provided interpretations of all ultrasounds in a blinded fashion. Statistical analysis was used to assess the utility of absence of gallbladder on US in predicting BA, confirmed intraoperatively. Results: Absent gallbladder on US predicts absent gallbladder with 77% accuracy, 92% sensitivity, 73% specificity, PPV 43%, and NPV 97% (P < 0.001, Fisher exact test). To diagnose BA, absent gallbladder on US has 66% accuracy, 53% sensitivity, 94% specificity, 96% PPV, and 46% NPV (P < 0.001, Fisher exact test). Conclusion: Sonographic gallbladder absence has high specificity and PPV, indicating utility for BA diagnosis; however, it is not useful for ruling out BA given its low sensitivity.

Rare case report of anorectal malformation and intestinal atresia.

INTRODUCTION: Intestinal malformations, such as intestinal atresia, malrotation, and anorectal malformation, are rare events, but concurrent intestinal atresia and anorectal malformation are rare in combination. These anomalies have similar in utero and perinatal symptoms, which can make the diagnosis of both defects prenatally challenging. PRESENTATION OF CASE: We present a case of a male infant with a prenatal diagnosis of truncus arteriosus who on a 32-week routine prenatal ultrasound was suspected to have an intestinal malformation. On day of life one, the patient was taken to the operating room and found to have both type IIIa ileal atresia and anorectal malformation with normal bowel in between. A complete work up for vertebral defects, anorectal malformation, cardiac septal defects, esophageal atresia, renal anomalies, and radial limb defects (VACTERL) anomalies did not reveal additional anomalies. DISCUSSION: In this case, prenatal information supported intestinal obstruction, and the rare combination of both intestinal atresia and anorectal malformation proved surprising and interesting. CONCLUSION: We suggest providers be aware of the potential of multiple alimentary tract malformations to improve operative preparation and reduce the morbidity or mortality risk from repeat procedures when possible.

Single site versus conventional laparoscopic appendectomy: some pain for no gain?

INTRODUCTION: The optimal laparoscopic appendectomy approach is not clear, comparing single site laparoscopic appendectomy (SILA) to conventional 3-port appendectomy (CLA). We investigated outcomes in pediatric patients comparing SILA to CLA: length of operation, length of stay, time to resumption of regular diet, follow up, rehospitalization, and cost. METHODS: Data was collected from children 1 to 18 years with appendectomy at Loma Linda University from 2018 to 2020, operated by two surgeons. Analysis utilized two-sample T, chi-squared, and Fisher's exact tests. RESULTS: Of 173 patients, 77 underwent SILA and 96 had CLA. There was no gender, age, or race difference between groups. Mean WBC was 17.5 × 103/mL in SILA group, compared to 15.3 × 103/mL in CLA group (P = 0.004). Operative time was 47.0 SILA compared to 49.5 minutes CLA (P = 0.269). Of SILA cases, 55.8% were simple appendicitis, while 53.3% of the CLA cases were simple (P = 0.857). Regular diet was resumed after 1.7 days in the SILA group, 1.1 days in CLA (P = 0.018). Length of stay was 2.9 days for SILA, 2.4 days for CLA (P = 0.144). Seven children required hospital readmission, 5 SILA and 2 CLA (P = 0.244). Five of the children who returned had intra-abdominal abscesses, of whom 4 had SILA. There was no difference in cost. CONCLUSIONS: The operative techniques had similar outcomes and operative times. There was a trend toward more intra-abdominal abscesses in the SILA group. Further study and longer follow up is needed to determine if there is an advantage to one laparoscopic approach over another.

Antenatal Diagnosis of Retroperitoneal Cystic Mass: Fetiform Teratoma or Fetus in Fetu? A Case Report.

BACKGROUND Teratoma, a tumor containing a variety of tissues, is a broad diagnosis containing mature teratoma, immature teratoma, and teratomas with malignant transformation. The tumor forms during embryological development secondary to unsuccessful migration of primordial germ cells. A specific type of mature teratoma, containing human-like features, is called a fetiform teratoma. The fetiform teratoma is often compared and confused with fetus in fetu, a reabsorbed twin. While these tumors have commonly been described in the gonads, the retroperitoneal location finding on antenatal imaging is rare. The distinction between the aforementioned subtypes is not well established, proving a challenging diagnosis prior to resection. CASE REPORT We present a case of a newborn male with a prenatal diagnosis of retroperitoneal cystic mass. Although prenatal imaging was obtained, the diagnosis remained unclear. After birth, planned surgical excision on day of life 7 showed the suprarenal mass contained contiguous intestinal elements. Histopathology examination revealed a mature cystic teratoma with multiple tissue types, including colonic, brain, respiratory, lymphatics, and nerves, reminiscent of fetiform teratoma. This case report presents an interesting example of differentiating elements straddling the diagnoses mentioned above. CONCLUSIONS This is the first reported case of fetiform teratoma diagnosed in a newborn and is especially unique for having the element of intestinal duplication within the retroperitoneal mass. The differentiating features of fetus in fetu and fetiform teratoma depend on subjective distinctions. The case provides an opportunity to discuss the differentials and management strategies.

Paraspinal plexiform schwannoma of unknown nerve origin: A case report.

INTRODUCTION AND IMPORTANCE: Schwannomas are benign, slow-growing nerve sheath tumors of neoplastic Schwann cells. They are the most common peripheral nerve tumors in adults and are typically discovered incidentally due to their asymptomatic presentation. Despite the fact that most schwannomas are unassociated with a syndrome, their etiology is thought to be related to alterations or loss of the neurofibromatosis type two tumor suppressor gene. CASE PRESENTATION: We present the case of a fifteen-year-old female who presented with a recurrent lower back/upper buttocks 9 cm mass with imaging suspicious for schwannoma. Needle biopsy revealed an S100 positive cellular schwannoma with patchy Ki-67. During surgical dissection down to the sacrum, no nerve of origin was identified. CLINICAL DISCUSSION: Schwannomas have no pathognomonic findings on MRI and may occur at any location that Schwann cells are present; therefore, confirming a diagnosis relies on histopathology. Plexiform schwannomas are defined by a "network-like" intraneural growth pattern and are exceedingly rare in paediatric populations. A location distinct from the spinal canal is also very rare as schwannomas typically originate from the head and neck region. CONCLUSION: Paediatric plexiform schwannomas have been rarely reported. Surgical planning relies on multiple factors such as tumor size, tumor location, pathologic features and symptomatic burden. The distinctive features of this case including an unknown nerve origin and a location outside the spinal canal provide a unique opportunity to discuss the diagnosis and management of paraspinal schwannomas and the impact on operative planning when a nerve of origin is not identified.