A surgical activity model of laparoscopic cholecystectomy for co-operation with collaborative robots.

BACKGROUND: Laparoscopic cholecystectomy is a very frequent surgical procedure. However, in an ageing society, less surgical staff will need to perform surgery on patients. Collaborative surgical robots (cobots) could address surgical staff shortages and workload. To achieve context-awareness for surgeon-robot collaboration, the intraoperative action workflow recognition is a key challenge. METHODS: A surgical process model was developed for intraoperative surgical activities including actor, instrument, action and target in laparoscopic cholecystectomy (excluding camera guidance). These activities, as well as instrument presence and surgical phases were annotated in videos of laparoscopic cholecystectomy performed on human patients (n = 10) and on explanted porcine livers (n = 10). The machine learning algorithm Distilled-Swin was trained on our own annotated dataset and the CholecT45 dataset. The validation of the model was conducted using a fivefold cross-validation approach. RESULTS: In total, 22,351 activities were annotated with a cumulative duration of 24.9 h of video segments. The machine learning algorithm trained and validated on our own dataset scored a mean average precision (mAP) of 25.7% and a top K = 5 accuracy of 85.3%. With training and validation on our dataset and CholecT45, the algorithm scored a mAP of 37.9%. CONCLUSIONS: An activity model was developed and applied for the fine-granular annotation of laparoscopic cholecystectomies in two surgical settings. A machine recognition algorithm trained on our own annotated dataset and CholecT45 achieved a higher performance than training only on CholecT45 and can recognize frequently occurring activities well, but not infrequent activities. The analysis of an annotated dataset allowed for the quantification of the potential of collaborative surgical robots to address the workload of surgical staff. If collaborative surgical robots could grasp and hold tissue, up to 83.5% of the assistant's tissue interacting tasks (i.e. excluding camera guidance) could be performed by robots.

Analytic representative element rate decline models for naturally fractured reservoir depletion.

Representative single anisotropic matrix block 2D Green's function models for depletion through fully-penetrating, vertical fractures through different numbers of fracture faces are constructed that analytically capture both fracture and block depletion with fracture-matrix mass transfer. The 1D Green's function for a fracture system is likewise solved in terms of the time evolution of average fracture pressure. While transient average pressure values are not inherently measurable, they are transformed into cumulative production or instantaneous flowrate values, thus producing new rate decline model functional forms. Primary variables in assembling the interacting systems model are the volume ratio, Vf /Vm, permeability ratio, kf /kx, and geometry, (a/b)(ky/kx), with the last term accounting for both block shape and permeability anisotropy. We construct interacting systems models in terms of various ratios of Vf /Vm, and kf /kx for three fracture architecture prototypes: representative matrix blocks depleted by 4, 2, or 1 contacting fractures. The single matrix block models can be migrated to ones for heterogeneous systems using superposition and matrix block distributions, as demonstrated with a binary distribution of block sizes with variable fractions. Analytic solutions for rate decline problems can be used to understand the production signatures of naturally fractured reservoirs and interpretation of fracture volume fraction, permeability ratio, average matrix block size, and measures of heterogeneity.

PLA2G6-associated neurodegeneration (PLAN): further expansion of the clinical, radiological and mutation spectrum associated with infantile and atypical childhood-onset disease.

Phospholipase A2 associated neurodegeneration (PLAN) is a major phenotype of autosomal recessive Neurodegeneration with Brain Iron Accumulation (NBIA). We describe the clinical phenotypes, neuroimaging features and PLA2G6 mutations in 5 children, of whom 4 presented with infantile neuroaxonal dystrophy (INAD). One other patient was diagnosed with the onset of PLAN in childhood, and our report highlights the diagnostic challenges associated with this atypical PLAN subtype. In this series, the neuroradiological relevance of classical PLAN features as well as apparent claval hypertrophy' is explored. Novel PLA2G6 mutations were identified in all patients. PLAN should be considered not only in patients presenting with a classic INAD phenotype but also in older patients presenting later in childhood with non-specific progressive neurological features including social communication difficulties, gait disturbance, dyspraxia, neuropsychiatric symptoms and extrapyramidal motor features.

Promoter mutation is a common variant in GJC2-associated Pelizaeus-Merzbacher-like disease.

Pelizaeus-Merzbacher-like disease (PMLD) is a clinically and genetically heterogeneous neurological disorder of cerebral hypomyelination. It is clinically characterised by early onset (usually infantile) nystagmus, impaired motor development, ataxia, choreoathetoid movements, dysarthria and progressive limb spasticity. We undertook autozygosity mapping studies in a large consanguineous family of Pakistani origin in which affected children had progressive lower limb spasticity and features of cerebral hypomyelination on MR brain imaging. SNP microarray and microsatellite marker analysis demonstrated linkage to chromosome 1q42.13-1q42.2. Direct sequencing of the gap junction protein gamma-2 gene, GJC2, identified a promoter region mutation (c.-167A>G) in the non-coding exon 1. The c.-167A>G promoter mutation was identified in a further 4 individuals from two families (who were also of Pakistani origin) with clinical and radiological features of PMLD in whom previous routine diagnostic screening of GJC2 had been reported as negative. A common haplotype was identified at the GJC2 locus in the three mutation-positive families, consistent with a common origin for the mutation and likely founder effect. This promoter mutation has only recently been reported in GJC2-PMLD but it has been postulated to affect the binding of the transcription factor SOX10 and appears to be a prevalent mutation, accounting for ~29% of reported patients with GJC2-PMLD. We propose that diagnostic screening of GJC2 should include sequence analysis of the non-coding exon 1, as well as the coding regions to avoid misdiagnosis or diagnostic delay in suspected PMLD.

Sinusitis complicated by meningitis: current management.

OBJECTIVES: Meningitis is the most common intracranial complication of sinusitis. We review the incidence, current management, outcomes, and complications of this serious infection. Our study also examines the evolving roles of endoscopic sinus surgery and other new therapeutic and diagnostic modalities in our armamentarium. STUDY DESIGN: A retrospective chart review was performed at a tertiary academic medical center of all patients diagnosed with sinusitis with complications between January 1985 and December 1999. METHODS: The patients were divided into two main groups: intracranial versus orbital complications. Meningitis was the most common intracranial complication. Data on patients with sinusitis and meningitis were collected and analyzed. RESULTS: Intracranial complications were present in 39 of 82 patients whereas orbital complications were noted in 43 patients. Twenty-one of the 39 intracranial complications were meningitis. The most common computed tomography finding in adults (54%) was sphenoid sinusitis. All patients with AIDS (6 of 21) had unique cryptococcus meningitis. In patients without AIDS, the most common organism was Streptococcus pneumoniae (10 of 21). The most common sequela was seizure disorder (4 of 21). Endoscopic sinus surgery was performed on 7 of 21 patients. One patient with AIDS who had sinusitis and meningitis died. CONCLUSIONS: Meningitis as a complication of sinusitis may still pose a serious threat. Although outcomes are encouraging, sequelae such as seizure disorders and hearing loss are common complications. The introduction of high-resolution computed tomography scans and magnetic resonance imaging and the availability of wide-spectrum antibiotics have improved our management significantly.

Evaluation of the utility and cost-effectiveness of obtaining histopathologic diagnosis on all routine tonsillectomy specimens.

OBJECTIVES: To evaluate the use and necessity of obtaining histopathology on patients undergoing tonsillectomy, and to provide indications and guidelines for requesting histopathology on tonsillectomy patients. STUDY DESIGN: At the University of Mississippi Medical Center, we have been routinely obtaining histopathologic diagnoses on every patient undergoing tonsillectomy or tonsillectomy and adenoidectomy. Specimens are separated into left and right tonsils and adenoids. This study was designed at our tertiary care academic center to evaluate the necessity for obtaining histopathologic diagnosis on each of these patients. METHODS: A retrospective review of histopathologic reports on all patients in both pediatric and adult age groups undergoing tonsillectomy or tonsillectomy and adenoidectomy between January 1994 and December 1999 was performed. RESULTS: A total of 2438 reports were reviewed. There were 2099 in the pediatric age group and 339 were adults. None of the children had an unusual histopathology finding other than lymphoid hyperplasia. Of the 339 adults, 34 had squamous cell carcinoma and 6 had lymphoma; however, these findings were suspected preoperatively by history and clinical manifestations. CONCLUSIONS: The general practice guidelines mandate obtaining histopathologic diagnoses on most of the tissues received. Based on our review, histopathology of tonsillectomy and/or adenoidectomy may not be necessary, especially in children. In this era of cutting excess costs of health care dollars, waving histopathology in these cases may have major implications without compromising delivery of quality care.

Pediatric functional endoscopic sinus surgery: is a second look necessary?

Functional endoscopic sinus surgery (FESS) has become the surgical procedure of choice for the treatment of chronic sinusitis that is refractory to medical treatment. It has become routine to perform endoscopy in children under general anesthesia 2 to 3 weeks after FESS to facilitate examination and cleaning of the operative site. We compared the clinical outcome of 50 children who underwent FESS without a second-look endoscopy with 50 children who underwent a routine second look. Patients with systemic disease (cystic fibrosis, immotile ciliary syndrome, immunoglobulin deficiency) or undergoing a revision procedure were excluded from the study. The results show that the postoperative improvement in nasal obstruction, nasal drainage, and chronic cough was the same for both groups. We conclude that in the vast majority of children without systemic disease and not undergoing a revision procedure, a second endoscopic procedure may not offer any apparent advantage.

Subglottic stenosis complicating cardiac surgery in children.

OBJECTIVE: To highlight the incidence of subglottic stenosis (SGS) as a complication of surgery for congenital heart disease and the role of single-stage laryngotracheoplasty in treating this complication. DESIGN: Retrospective case series. SETTING: University-based referral center specializing in surgery for congenital heart disease and complex airway problem management. INTERVENTION: Laryngotracheal reconstruction (LTR). MAIN OUTCOME MEASURE: Successful airway expansion. RESULTS: At last follow-up, 87.5% (7 of 8) of patients remain free of obstructive airway symptoms. CONCLUSION: SGS can complicate surgery for congenital heart disease in children. Single-stage LTR is an effective treatment modality for this problem.

Peritonsillar abscess in early childhood. Presentation and management.

OBJECTIVE: To highlight the modes of presentation and management of a peritonsillar abscess in children younger than 5 years. DESIGN: Retrospective case series. SETTING: Tertiary referral pediatric otolaryngology practice. PATIENTS: Seven children younger than 5 years. RESULTS: The mean age of the children studied was 27 months (age range, 7-41 months). Five (71%) of the 7 patients underwent computed tomographic scanning to confirm the diagnosis. Pus was cultured at surgery in every case. The most common organism detected was Streptococcus viridans. The average hospital stay was 72 hours (range, 22 hours to 12 days). After diagnosis of an abscess, all patients underwent an electrocautery tonsillectomy and had an uneventful recovery. CONCLUSIONS: Children younger than 5 years who present with poor oral intake, high fever, drooling, and trismus should be suspected of having a peritonsillar abscess. A computed tomographic scan of the neck is usually required to confirm a suspected diagnosis. Prompt diagnosis and treatment will lead to a considerable decrease in morbidity. Immediate tonsillectomy is a safe and effective means of abscess drainage.

Laryngotracheal reconstruction without stenting.

Many surgical procedures, including laryngotracheal expansion with or without grafting, have been suggested for repairing laryngotracheal stenosis in children, and although a variety of stents have been described, the practice of prolonged stenting continues to diminish. We describe 21 pediatric patients with moderate-to-severe subglottic or tracheal stenosis who had laryngotracheal reconstructions with anterior rib cartilage grafts without stenting or intubation. The patients were between 6 months and 7 years of age at the time of surgery. All patients were extubated in the operating room after the procedure was terminated. One patient required reintubation in the intensive care unit for 48 hours after surgery, and another patient required a tracheotomy. Wound infection occurred in one patient. Most patients were discharged to their homes 3 to 5 days after surgery. We report the indications, technique, results, and complications of laryngotracheal reconstruction using a rib graft without stenting.

Management of medial subperiosteal abscess of the orbit in children--a 5 year experience.

A medial subperiosteal abscess (SPA) of the orbit is the most common serious complication of sinusitis in children. The distinction between SPA and the more benign pre-septal disease is difficult to make especially in a young child in whom an ophthalmological evaluation is often difficult. Computerised tomography (CT) is the investigation of choice in making this distinction. Subperiosteal inflammatory disease of the orbit is initially treated with intravenous antibiotic therapy with surgery reserved for those patients who do not respond to medical treatment and in whom a medial SPA is confirmed by CT. Conventionally, the abscess is drained via an external incision and an ethmoidectomy is performed at the same time. More recently, successful drainage of SPA's has been accomplished endoscopically via a intranasal approach with less morbidity and superior cosmesis. We present a 5 year experience of 24 patients with CT scans suggestive of medial SPA who underwent endoscopic exploration of the medial subperiosteal orbital space. We discuss the current management of medial subperiosteal disease of the orbit in children and include a review of the literature. Also included is a clinical staging system which aids the management of orbital complications of sinusitis.

The management of asymptomatic firearm injuries in children.

Paediatric firearm injuries in the UK are uncommon. We present two children with BB-gun pellets in the parapharyngeal space who were managed conservatively and remained asymptomatic 6 months after the gunshot injury. The management of asymptomatic firearm injuries in children is discussed and a literature review included.

Campomelic syndrome--laryngotracheomalacia treated with single-stage laryngotracheal reconstruction.

The campomelic syndrome is a rare osteochondrodysplasia which frequently leads to early death from pulmonary insufficiency. We describe a patient with anatomic compromise of the upper airway due to diffuse laryngotracheomalacia and a moderate subglottic stenosis, treated successfully with single-stage laryngotracheal reconstruction using a rib graft. To our knowledge this has not been previously described. A review of the current literature is included.

Bilateral fat graft myringoplasty in children.

The results after simultaneous bilateral fat graft myringoplasties in children have not been previously reported in the literature. We report on 28 children who underwent bilateral fat graft myringoplasties as outpatient procedures under general anesthesia. The success rate was 91% at final follow-up, with only 16% of children requiring insertion of pressure-equalizing (PE) tubes following surgery. No complications were documented. We concluded that bilateral fat graft myringoplasties are safe to perform, with an excellent success rate, and are suitable as outpatient procedures.

Criteria for success in pediatric functional endonasal sinus surgery.

Functional endonasal sinus surgery (FESS) is widely used in the treatment of chronic sinusitis in adults and children. Although success rates of 80% to 93% have been reported, no criteria for success or improvement have been suggested. Standardized measures are needed to assess the outcome of FESS and to compare the results obtained by different surgical teams and for various patient groups. After reviewing the charts of 500 pediatric patients who underwent FESS between July 1987 and June 1992, the authors of this study formalized criteria for assessing the outcome of surgery.

Delayed toxic shock syndrome after functional endonasal sinus surgery.

Toxic shock syndrome (TSS) is an uncommon, severe, multisystem illness that may follow any surgical procedure. It usually occurs in the immediate postoperative period and is manifested by the sudden onset of a high fever and a variety of other signs and symptoms. The reported incidence of TSS after nasal surgery is 16 cases per 100,000 patients. We report five unusual cases of delayed TSS that occurred after functional endonasal sinus surgery in which no packing was used. Toxic shock syndrome developed in three children and two adults 5 days to 5 weeks postoperatively. All patients were treated successfully with no sequelae. The pathophysiologic features, clinical manifestations, and treatment of TSS are described in detail.

Transnasal repair of choanal atresia using telescopes.

OBJECTIVE: Choanal atresia, consisting of a unilateral or bilateral bony or membranous septum between the nose and the pharynx, occurs in approximately one of 7000 live births. Conventional treatment has consisted of watchful observation and elective surgical repair or immediate intervention using a variety of surgical techniques. We attempted transnasal repair using a telescope to remedy the obstruction. PATIENTS: Over an 18-month period, six female and four male patients, who were between 3 weeks and 14 years of age at the time of surgery, underwent transnasal repair of unilateral or bilateral choanal atresia with the aid of a rod-lens telescope. All 10 patients had nasal stents made from endotracheal tubes that were fixed with sublabial and transseptal sutures. RESULTS: Seven patients remain free of symptoms 18 to 24 months after surgery. Three patients required revision surgery. Two of the revision cases recovered completely, with no restenosis 12 months after the second surgery. There were no postoperative complications. CONCLUSION: Transnasal repair of choanal atresia using a rod-lens telescope appears to be an effective procedure with low morbidity.

Cavernous sinus thrombosis: successful treatment using functional endonasal sinus surgery.

OBJECTIVE: Infections of the paranasal sinuses can be complicated by septic thrombosis of the cavernous venous sinuses. After standard antibiotic treatment, fewer than 50% of the patients recover completely, and the mortality rate is approximately 30%. We chose to treat this potentially catastrophic complication with functional endonasal sinus surgery in addition to standard antibiotic therapy. DESIGN: Case study. PATIENT: A 15-year-old boy presented to the emergency room of LeBonheur Children's Medical Center, Memphis, Tenn, with right proptosis, chemosis, ptosis, ophthalmoplegia, cranial nerve palsies, and paresthesia. The physical examination and computed tomographic scans of the sinuses and orbits revealed edema of the right orbit and pansinusitis, with secondary right cavernous sinus thrombosis and right superior ophthalmic vein thrombosis. INTERVENTION: The patient was started on a regimen of cefuroxime and nafcillin sodium and was scheduled for emergency functional endonasal sinus surgery to drain the primary sites of infection. After surgery, the patient was placed on a 3-week regimen of cefotaxime sodium, metronidazole hydrochloride, vancomycin hydrochloride, and heparin sodium. RESULTS: During surgery, the frontal recess and ethmoid, sphenoid, and maxillary sinuses were found to be filled with polypoid tissue and purulent material. Functional endonasal sinus surgery restored the sinuses to their normal physiologic state. The sinuses demonstrated the progress observed clinically. CONCLUSIONS: The improvement in outcome effected by standard antibiotic therapy can be significantly augmented by using functional endonasal sinus surgery in the treatment of cavernous sinus thrombosis.