Anatomy and surgery of the infected dermal sinus of the lower spine

Surgical Outcome of Spinal Subdural Abscesses: A Report of Four Consecutive Patients and Brief Review of the Literature

BACKGROUND AND STUDY AIMS

 Spinal subdural abscesses (SSAs) are rare and have a poor prognosis, especially when they are diagnosed late. In the literature, most cases of SSAs have been reported as case reports and small case series. In this study, we aimed to evaluate the surgical outcomes of four consecutive SSA patients.

MATERIAL AND METHODS

 In this retrospective study, we reviewed the medical charts of four SSA patients who underwent surgical intervention at two neurosurgical centers from September 2012 to September 2019.

RESULTS

 Our series comprised four patients (three females and one male) with SSA (intradural-extramedullary) who were treated surgically. Holocord SSA was observed in two patients. The mean age was 15.1 ± 17.1 years. Unsteady gait and weakness of legs was the presenting symptom in all patients. The mean preoperative course was 5.3 ± 3.4 weeks. The causative pathogens were methicillin-resistant Staphylococcus aureus (MRSA), Escherichia coli, and Mycobacterium tuberculosis. In the fourth case, the pathogen was non-M. tuberculosis. In the 44th postoperative month, the patient underwent surgery for an intramedullary abscess. The causative pathogen was E. coli. Except for one adolescent male who was paraplegic at presentation, improvement was observed in all patients at their last follow-up after 54.0 ± 35.9 months after surgery.

CONCLUSION

 Early diagnosis and urgent surgical intervention are essential for a good prognosis in SSA cases. We recommend drainage followed by appropriate antibiotics.

Focal Spinal Nondisjunctional Disorders: Including a Discussion on the Embryogenesis of Cranial Focal Nondisjunctional Lesions

The publication of a comprehensive report on limited dorsal myeloschisis by the senior author (DP) in 2010 has brought full attention to the concept of limited myeloschisis that he first formulated in 1992 and ignited interests in the whole spectrum of focal spinal nondisjunctional disorders. Now that focal nondisjunctional disorders have become well known, new clinical reports on these conditions or relevant subjects are frequently seen. Here we present an updated review on the full spectrum of focal spinal nondisjunctional disorders and extend the scope to include a discussion on the embryogenesis of cranial focal nondisjunctional malformations.

Spinal Dermoid and Epidermoid Cyst: An Institutional Experience and Clinical Insight into the Neural Tube Closure Models

Objectives  The spinal dermoid and epidermoid cysts (SDECs) are rare entities comprising less than 1% of pediatric intraspinal tumors. The present study aims to extrapolate the clinicoradiological data, in order to identify the most plausible neural tube closure model in human and provide a retrospective representation from our clinical experience.

Materials and Methods  We collected the details of all histologically proven, newly diagnosed primary SDECs who underwent excision over the past 20 years. Secondary or recurrent lesions and other spinal cord tumors were excluded. Surgical and follow-up details of these patients as well as those with associated spinal dysraphism were reviewed. Clinical and radiological follow-up revealed the recurrence in these inborn spinal cord disorders.

Results  A total of 73 patients were included retrospectively, having a mean age of 22.4 ± 13.3 years, and 41 (56.2%) cases fell in the first two decades of life. Twenty-four (32.9%) dermoid and 49 (67.1%) epidermoid cysts comprised the study population and 20 of them had associated spinal dysraphism. The distribution of SDECs was the most common in lumbosacral region ( n = 30) which was 10 times more common than in the sacral region ( n = 3). Bladder dysfunction 50 (68.5%) and pain 48 (65.7%) were the most common presenting complaints. During follow-up visits, 40/48 (83.3%) cases showed sensory improvement while 11/16 (68.7%) regained normal bowel function. There was no surgical mortality with recurrence seen in eight till the last follow-up.

Conclusions  The protracted clinical course of the spinal inclusion cysts mandates a long-term follow-up. The results of our study support the multisite closure model and attempt to provide a retrospective reflection of neural tube closure model in humans by using SDECs as the surrogate marker of neural tube closure defect.

Focal Spinal Nondisjunction in Primary Neurulation : Limited Dorsal Myeloschisis and Congenital Spinal Dermal Sinus Tract

Spinal dysraphic lesions due to focal nondisjunction in primary neurulation are commonly encountered in paediatric neurosurgery, but the “fog-of-war” on these conditions was only gradually dispersed in the past 10 years by the works of the groups led by the senior author and Prof. Kyu-Chang Wang. It is now clear that limited dorsal myeloschisis and congenital spinal dermal sinus tract are conditions at the two ends of a spectrum; and mixed lesions of them with various configurations exist. This review article summarizes the current understanding of these conditions’ embryogenetic mechanisms, pathological anatomy and clinical manifestations, and their management strategy and surgical techniques.

Pediatric Spinal Subdural Abscesses: A Report of Three Consecutive Patients

BACKGROUND

Despite technological advances in medical treatment, the prognosis of the rarely reported spinal subdural abscesses (SSAs) has remained a serious entity largely unaffected, especially when they are diagnosed late. In this study, the authors aimed to present the surgical outcomes of 3 consecutive pediatric patients with SSA.

MATERIALS AND METHODS

We retrospectively reviewed the medical records of pediatric patients with spinal lesions who underwent surgery at 2 neurosurgical centers spanning 7 years, from 2012 to 2019. All pediatric patients who were diagnosed with SSA (n = 3) were selected as the core sample for this study.

RESULTS

Three pediatric patients (2 females and 1 male) with SSA were surgically treated. Holocord SSA was observed in 1 patient. The mean age was 7.1 ± 7.7 years. The most common presenting symptoms were gait disturbance and weakness of lower extremities (100%). The mean preoperative course was 5.7 ± 4.0 weeks. The causative pathogens were Escherichia coli (E. coli) and M. tuberculosis. In the 2nd case, the pathogen was non-tuberculosis mycobacterium in the extramedullary abscess. In the 44th postoperative month, she underwent surgery for intramedullary abscess. The causative pathogen was E. coli. Except for 1 male adolescent who presented with severe clinical status (paraplegic), the improvement was observed in all patients at their last follow-up after 50.3 ± 43.5 months of average.

CONCLUSIONS

Drainage followed by appropriate antibiotics is the optimal treatment for SSAs. Early diagnosis and urgent surgical treatment are essential for a good prognosis. All surgically treated SSA patients with neurological deficits were rehabilitated with physical therapy postoperatively.

Dorsal dermal sinus presenting as quadriparesis

Dorsal dermal sinus (DDS) represents the spectrum of spinal dysraphism. Children may present with features of meningitis. A 13-month male child presented with features of meningitis and quadriparesis. Clinical examination revealed a small pit over the thoracic spine. MRI was suggestive of a DDS. Initially, the patient responded to antibiotics and methylprednisolone, which was given for resolving the mass effect. However, he had a recurrence of symptoms and underwent surgical exploration and resection of DSS with resolution of symptoms. Careful examination of the back is extremely essential in children with meningitis. Radiological investigation helps in visualisation of the DSS. Although rare in children, they may present with recurrent meningitis.

Limited Dorsal Myeloschisis and Congenital Dermal Sinus: Comparison of Clinical and MR Imaging Features

BACKGROUND AND PURPOSE

While limited dorsal myeloschisis is a distinctive form of spinal dysraphism, it may be confused with congenital dermal sinus. The aim of this study was to describe clinical and MR imaging findings of limited dorsal myeloschisis that can distinguish it from congenital dermal sinus.

MATERIALS AND METHODS

We retrospectively reviewed the clinical and MR imaging findings of 12 patients with limited dorsal myeloschisis and 10 patients with congenital dermal sinus. Skin abnormalities, neurologic deficits, and infectious complication were evaluated on the basis of clinical information. We evaluated the following MR imaging features: visibility of the tract along the intrathecal course, attachment site of the tract, level of the conus medullaris, shape of the spinal cord, and presence of intradural lesions such as dermoid/epidermoid tumors.

RESULTS

A crater covered with pale epithelium was the most common skin lesion in limited dorsal myeloschisis (10/12, 83%). Infectious complications were common in congenital dermal sinus (6/10, 60%), whereas none were found in limited dorsal myeloschisis (P = .003). The following MR imaging findings were significantly different between the 2 groups (P < .05): 1) higher visibility of the intrathecal tract in limited dorsal myeloschisis (10/12, 83%) versus in congenital dermal sinus (1/10, 10%), 2) the tract attached to the cord in limited dorsal myeloschisis (12/12, 100%) versus various tract attachments in congenital dermal sinus, 3) dorsal tenting of the cord in limited dorsal myeloschisis (10/12, 83%) versus in congenital dermal sinus (1/10, 10%), and 4) the presence of dermoid/epidermoid tumors in congenital dermal sinus (6/10, 60%) versus none in limited dorsal myeloschisis.

CONCLUSIONS

Limited dorsal myeloschisis has distinct MR imaging features: a visible intrathecal tract with dorsal tenting of the cord at the tract-cord union. Limited dorsal myeloschisis was not associated with infection and dermoid/epidermoid tumors.

Streptococcus pneumoniae meningitis complicated by an intramedullary abscess: a case report and review of the literature

BACKGROUND

Intramedullary abscess is a rare neurosurgical condition that usually arises in the setting of penetrating trauma to the spinal cord, infected congenital dural sinuses, or tuberculosis.

CASE PRESENTATION

We describe a case of a 35-year-old African American male who presented with sepsis and a clinical picture of meningitis. The patient continued to have declining neurological status with decreasing sensation and worsening motor strength in all four extremities. He was found to have an intramedullary abscess in the cervical spinal cord that was treated with a decompressive posterior cervical laminectomy and drainage. The patient began to have a partial recovery of neurological function postoperatively. We also review the literature on intramedullary abscess that suggests the clinical presentation of our patient was a rare complication of acute meningitis.

CONCLUSIONS

Intramedullary abscess formation is a rare entity, and a high index of suspicion for intramedullary abscess is the key for making the diagnosis and expediting treatment for these patients.

Spinal inclusion cysts

BACKGROUND

Dermoid and epidermoid tumours are related though pathologically distinct entities that can be combined under the term inclusion cysts. Most are of developmental origin and in the spine may be intramedullary, intradural extramedullary or extraspinal in location. The terminology, aetiology, radiology and optimal management of spinal inclusion cysts have been the source of ongoing controversy.

AIMS

A retrospective review of surgical cases from a single institution has been conducted, and this experience is discussed in the context of the existing literature.

RESULTS

Sixteen cases of paediatric spinal inclusion cysts were treated between 2002 and 2012. Associated anomalies included dermal sinus track (11), previous myelomeningocele (4) and Currarino syndrome (1). The lesions spanned 1-8 spinal levels; in half the cases, there was a history of secondary infection at the time of presentation. The aim of treatment was complete excision, and macroscopic removal was achieved in all cases. The most significant adverse outcome was related to sphincter dysfunction, and this was observed in four cases, two with a prior history of myelomeningocele and two who had presented with active infection. No instances of recurrence were recorded during a median follow up of 7.4 years (range 1-11 years).

CONCLUSIONS

Spinal inclusion cysts are aetiologically diverse lesions, though in paediatric practice, most occur in association with a dysraphic anomaly. There are no consistent clinical or radiological features that will reliably distinguish between dermoid and epidermoid, and both may result in symptoms from mass effect or infection. The recurrence rate is low if complete macroscopic resection can be achieved.

Infections of the spinal subdural space in children: a series of 11 contemporary cases and review of all published reports. A multinational collaborative effort

INTRODUCTION

Positioned anatomically between the spinal epidural space and the intramedullary compartment, the spinal subdural space remains the least common area of localized infection in the central nervous system. Infectious processes of the subdural spinal space include subdural spinal empyema, subdural spinal abscess, infected spinal subdural cyst, and infectious spinal subdural cyst. To date, there has been no systematic review of these entities in children, with the cumulative knowledge of the pathophysiologic, microbiologic, and demographic characteristics of these infections relegated solely to few small series and case reports.

METHODS

A series of 11 recent cases culled from the collaboration of international authors are presented. In addition, an exhaustive MEDLINE search and manual review of the international literature was performed, identifying a total of 73 cases of spinal subdural infections in patients under the age of 21. Data of interest include the age, sex, signs, and symptoms at presentation, spinal location of infection, presence of spinal dysraphism, and other comorbidities, offending organism, treatment, outcome, and follow-up.

RESULTS

Patients ages ranged from 4 weeks to 20 years (mean, 6.5 years). Males outnumbered females by a ratio of 2:1. Over half (53 %) of spinal subdural infections in children were associated with spinal dysraphism or other congenital abnormalities of the spine. The commonest organism to infect the spinal subdural space in children is mycobacterium tuberculosis and the thoracic spinal region was most commonly infected.

CONCLUSIONS

The disease is usually treated surgically, although a more expectant approach consisting of antibiotics and observation has also been proposed.

En bloc excision of a dermal sinus tract

Dermal sinus tracts are a form of spinal dysraphism that arises from a failure of dysjunction early in embryogenesis. They are diagnosed in pediatric patients and who present with a dimple, infection, or neurologic deficit. The tract is surgically excised en bloc to avoid contamination from the tract, which harbors bacteria. However, dermal sinus tracts typically terminate intradurally, rendering their en bloc excision difficult. To avoid entering the tract, allowing for an en bloc excision, we modified the usual technique employed for accessing the spinal intradural space. An en bloc excision of the dermal sinus tract was successfully performed. The patient recovered from the procedure neurologically intact and her postoperative course was uncomplicated. We conclude that en bloc excision of a dermal sinus tract down to the intradural space is feasible with modifications to standard operative technique.

Dermal sinus tract of the spine

OBJECTIVE

Spinal dermal sinus tract (DST) is a rare entity which usually comes to clinical attention by cutaneous abnormalities, neurologic deficit, and/or infection. We performed this study to assess presentation patterns, associated anomalies, radiologic, urologic, and surgical findings in children afflicted with spinal DST.

METHODS

Medical records of 35 children treated for spinal DST in Children's Medical Center from January 2001 to December 2008 were reviewed.

RESULTS

Patients' age ranged from 3 days to 8.44 years. Dermal sinuses were located most frequently in the lumbar and lumbosacral regions. The most common causes for referral were abnormal skin findings (57.1%) and infection (31.4%). Notably eight patients presented with meningitis. The overall rate of neurologic abnormalities was 37.1%, four of whom presented acutely with rapidly progressive paraplegia and meningitis. The most common magnetic resonance imaging finding was tethered cord (63%). At least one urological evaluation was performed in 30 patients, which revealed abnormal results in 77% of them. All patients underwent complete resection of the tract and repair of associated abnormalities. Most tracts terminated within the intradural space. Fifteen patients (42.8%) had inclusion tumor with the dermoid tumor being the most common. None of the patients demonstrated neurological deterioration postoperatively.

CONCLUSION

Dermal sinus tract is an innocuous-appearing spinal dysraphism that may contribute to devastating morbidities if not timely addressed. In order to prevent complications, timely surgical intervention including complete resection of sinus tract with intradural exploration and correction of associated abnormalities is of utmost importance.

The spinal dermal-sinus-like stalk

OBJECTS

In this study, a disjunction anomaly mimicking the spinal congenital dermal sinus (DS) is described. This anomaly is referred to as the dermal-sinus-like stalk. Dissimilarities between a true dermal sinus and a dermal-sinus-like stalk are discussed.

CLINICAL MATERIAL

Three cases in which a spinal congenital dermal sinus was suspected are presented. A similar anatomical configuration, different from that of a dermal sinus, was found. All cases presented with a skin-covered dimple from which a solid tract was seen continuing intramedullary in two cases and intraspinally in one case. None of the patients presented with signs of infection or an associated dermoid-epidermoid tumor. Clinical, radiological, and surgical findings are discussed. A hypothesis is made on the pathological genesis of this malformation.

CONCLUSION

A dermal-sinus-like stalk is a malformation similar to a spinal congenital dermal sinus but is not associated with DS-related complications. Despite important clinical, radiological, surgical, and histopathological differences, it is difficult to distinguish this malformation from a true DS based on clinical and radiological examination alone. Therefore, surgical intervention, at the time of diagnosis, is recommended in all cases.

Spinal congenital dermal sinus in a chick embryo model. Laboratory investigation

OBJECT

The origin of spinal congenital dermal sinuses is not known. A local nondisjunction of the closing neural tube and the epidermal ectoderm is thought to be the cause of this malformation. In this experimental study, a nondisjunction was mimicked in chick embryos to create an animal model for the dermal sinus.

METHODS

A piece of amniotic tissue was implanted in the closing neural tube in ovo in chick embryos at 2 days of incubation. A total of 50 embryos were manipulated. After a further incubation time of 2-7 days, the embryos were macroscopically and histologically evaluated.

RESULTS

Dermal sinus-like anomalies were induced in 24 embryos. The induced abnormalities varied from superficial, epidermal lesions to epidermal dimples continuing as a strand of tissue toward the neural tube. This strand invariably was of nonneuronal origin. Additionally, in 3 embryos a split cord malformation was noted, most likely caused by damage to the neural tube during implantation.

CONCLUSIONS

Implantation of donor amniotic tissue in the closing chick neural tube does result in a dimple, from which a strand of tissue continues to the neural tube in various cases, indicating that formation of a dermal sinus-like anomaly can be successfully induced by experimental continuation of the connection between neural tube and surface ectoderm. This finding strengthens the hypothesis that a human dermal sinus arises after nondisjunction of neural tube and surface ectoderm.

Coexistence of a human tail and congenital dermal sinus associated with lumbosacral lipoma

We present a female baby with a human tail associated with congenital dermal sinus (CDS) at the caudal site of the tail. Magnetic resonance (MR) images with constructive interference in steady-state (CISS) sequencing clearly demonstrated a lumbosacral lipoma of caudal type, contiguous with the dermal sinus tract and not with the human tail. At 3 months old, the tail was surgically removed. The dermal sinus tract and contiguous lipoma were also resected, and untethering of the spinal cord was performed. Although both the human tail and CDS are frequently associated with spina bifida occulta, coexistence of the tail and CDS is exceedingly rare. CISS-MRI is useful for demonstrating the precise anatomical relationship between these complicated pathologies.

Infected intraparenchymal dermoids: an underestimated entity

Infection secondary to a dermal sinus most commonly occurs in the form of cutaneous, epidural, or subdural abscesses. Rarely, it can result in an intramedullary abscess as a result of a dermal sinus. This study presents a clinicoradiological profile of 19 cases harboring abscesses within the dermoids and highlights the importance of dermal sinus acting as a pathway for infections to enter the nervous system. Emergent exploration, pus drainage, and minimal abscess wall excision along with prolonged antibiotic administration remained the management of choice in all cases. Methicillin-sensitive Staphylococcus aureus was the commonest offending organism. In all, 7 patients recovered to normal neurological status, 5 showed no improvement, and 7 improved partially. Improvement in motor power was noted, albeit partially, but bladder functions failed to recover even at long-term follow-up. Even when such infective complications of dermal sinuses are rare, these are potentially serious and disabling.