Use of computer-aided three-dimensional prototyping to surgically assist in tooth autotransplantation

Autotransplantation is a surgical technique in which a donor tooth belonging to the same individual is repositioned into a surgically prepared socket or site of previous tooth extraction. It is beneficial in patients with teeth affected by agenesis, trauma, significant caries, and in teeth in a non-restorable condition or prognostically poor due to other pathology. It is particularly useful in paediatric patients, as properly transplanted teeth have a vital periodontium that allows for continuous growth and functional adaptation leading to preservation of the alveolar ridge. Technological advances in rapid prototyping combined with three-dimensional (3D) computed tomography (CT) have the ability to revolutionise autotransplantation. Preoperative planning for atraumatic extraction of the donor tooth and precise preparation of the recipient site with a rapid prototyped surgical template of the donor tooth considerably reduces the extra-alveolar time, and also reduces manipulation of the root sheath and periodontal ligament, and related trauma. This case series demonstrates the efficient and successful autotransplantation of various types of teeth with the use of a rapid prototyped surgical template produced from 3D CT. The use of this technology is expected to refine the surgical technique and improve treatment outcomes.

A study protocol for a randomised controlled trial evaluating the effects of intraoperative computed tomography on the outcomes of zygomatic fractures

Background

Zygomaticomaxillary complex (ZMC) and zygomatic arch (ZA) fractures are common injuries resulting from facial trauma and frequently require surgical management (Huang et al., Craniomaxillofac Trauma Reconstr 8(4):271-6, 2015). A substantial number of post-operative functional and cosmetic complications can arise from the surgical management of these fractures. These include scarring, inadequate facial profile restoration, facial asymmetries and diplopia (Ellis et al. J Oral Maxillofac Surg 54(4):386-400, 1996; Yang et al. Oral Maxillofac Surg Clin North Am 23(1):31-45, 2011; Kloss et al. Int J Oral Maxillofac Surg 40(1):33-7, 2011). Intuitively, most of these aforementioned complications arise as a result of inadequate fracture reduction; however, current standard practice is to assess reduction post-operatively through plain radiographs or computed tomography (CT) scans. The role of intra-operative CT scanning to assess the reduction of ZMC/ZA fractures and the potential impact on complications, has thus far not been established.

Methods

This is a prospective randomised controlled trial currently being undertaken at the Royal Brisbane and Women’s Hospital. All patients who require operative management of their ZMC or ZA fractures are offered enrollment in the trial. The patients are randomised into two groups: interventional (intra-operative CT) and control (no intra-operative CT). All patients in each group will have post-operative radiographs taken. From these radiographs, the reduction of the ZMC and/or ZA fracture is graded by a blinded assessor. Patients will be reviewed in clinic at 1 week and 6 weeks post-surgery. During these consultations, all patients will be assessed for scarring, diplopia, facial profile restoration and need for revision surgery.

Discussion

Many complications associated with surgical management of ZMC and ZA fractures involve poor aesthetic results as a direct consequence of inadequate fracture reduction. Inadequate fracture reduction is predictable given that small incisions are used and only limited visualisation of the fractures is possible during the procedure. This is due to a desire to limit scarring and reduce the risk of damage to vital structures in an aesthetically sensitive region of the body. It follows that an intraoperative adjunctive tool such as a CT scan, which can assist in visualisation of the fractures and the subsequent reduction, could potentially improve reduction and reduce complications.

Trial registration

Australian New Zealand Clinical Trials Registry, ACTRN12616000693426. Registered on 26 May 2016.

Electronic supplementary material

The online version of this article (10.1186/s13063-019-3625-8) contains supplementary material, which is available to authorized users.

Challenging behaviour and sleep cycle disorder following brain injury: a preliminary response to agomelatine treatment

BACKGROUND

Sleep disturbances are common after acquired brain injury. Sedatives can exacerbate behavioural disorders.

OBJECTIVES

This study reports the case of a severely brain damaged man (TM) who developed a non-24 hour sleep cycle disorder that was effectively managed by the administration of a melatonin receptor agonist, agomelatine.

METHOD

TM suffered significant brain damage as a result of a large subarachnoid haemorrhage of his right anterior cerebral artery complicated by midline shift and subsequent infarction of his left middle cerebral artery. In addition to challenging behaviour and cognitive impairment, TM presented with a recurrent disturbed sleep-wake pattern that significantly worsened his quality-of-life. He was diagnosed as suffering of non-24 hour sleep-wake disorder. Challenge was recorded using the Overt Aggression Scale Modified for Neuro-Rehabilitation (OASMNR).

RESULTS

Typical hypnotics had no or ill effects. Agomelatine prescription (25 mg) led to significant OASMNR and sleep efficiency change with effects apparent at 1.5 years later.

CONCLUSIONS

Administration of the melatonin receptor (MT₁ and MT₂) agonist agomelatine each night resulted in an immediate and sustained improvement on sleep and on indices of challenging behaviour.

Anterior cervical discectomy: to graft or not to graft?

The debate regarding whether to perform an interbody fusion after anterior cervical discectomy (ACD) has been going on for the last 50 years. Several prospective randomized clinical trials have been performed to evaluate the clinical outcome following anterior cervical discectomy with and without interbody fusion. None of these studies show a significant difference between the two techniques in terms of relief of arm pain or neck pain. The operative time, in-hospital stay and time for return to work seem to be slightly longer following anterior cervical discectomy with interbody grafting (ACDF) compared to ACD alone. However a temporary increase in postoperative axial pain seems to be a common complication following ACD. There is also no difference in the clinical outcomes between ACD and ACDF with plating and ACDF with interbody spacers. However, if a fusion procedure is undertaken, the use of interbody spacers does have the advantage of avoiding donor site complications. There is also some evidence to suggest that plate fixation can lead to increased fusion rates. There is a significant risk of a degree of segmental kyphosis following ACD. These radiological features, however, do not correlate with the clinical outcome. Radiological and clinical studies fail to show a significant difference in recurrence of foraminal narrowing or the rates of reoperation following ACD or ACDF. The available body of evidence suggests that the addition of a fusion procedure following anterior cervical decompression may give improved radiological results but does not necessarily result in improved clinical outcomes.

Multiple schwannomas: report of two cases

In this paper authors present two cases of multiple schwannomas without the features of neurofibromatosis (NF). The authors retrospectively reviewed the hospital charts, radiology films, operative notes and pathology slides of these two patients. There was no family history of neurofibromatosis. The two patients had contrast enhanced MRI, which was negative for vestibular schwannomas. Both underwent surgical excision of symptomatic lesions. Histopathology confirmed these lesions as schwannomas. Molecular genetic analysis in case 1 demonstrated two distinct mutations of the NF2 gene in two different schwannomas, with concomitant loss of heterozygosity in both tumours. In contrast peripheral blood lymphocytes did not reveal mutations of NF2. The authors recommend surgery for symptomatic lesions. Asymptomatic tumours can be monitored. Regular follow up is essential as they may develop fresh lesions at any time. The relevant literature is discussed.

Effect of catheter design on tracheal pressures during tracheal gas insufflation

BACKGROUND AND OBJECTIVE

This study investigated the distribution of pressures within a model trachea, produced by five different tracheal gas insufflation devices. The aim was to suggest a suitable design of a tracheal gas insufflation device for clinical use.

METHODS

Each device was tested using insufflation flow rates of 5 and 10 L min(-1). For each flow rate, the pressure within the tracheal model was measured at 33 fixed points.

RESULTS

The Boussignac tracheal tube produced the most even pressure distribution, while a reverse-flow catheter produced pressure changes of the smallest magnitude.

CONCLUSIONS

We suggest that catheters producing the lowest pressure changes are likely to be safer for clinical use.

GABAA receptor alpha 1 and beta 2 subunit null mutant mice: behavioral responses to ethanol

Mice lacking either the alpha1 or beta 2 subunit of the GABAA receptor were tested for ethanol, saccharin, or quinine consumption, ethanol-conditioned place preference, ethanol-conditioned taste aversion, ethanol-simulated motor activity, and handling-induced seizures following chronic consumption of an ethanol liquid diet. The alpha1 null mutants showed decreased ethanol and saccharin consumption, increased aversion to ethanol, and a marked stimulation of motor activity after injection of ethanol. The beta 2 null mutants showed decreased consumption of saccharin and quinine, but not ethanol. Surprisingly, neither mutant showed marked changes in handling induced seizures before or after withdrawal of ethanol. The unique effects of deletion of these two GABAA receptor subunits on ethanol responses are discussed in terms of the distinct changes in different populations of GABAA receptors.

Alcohol actions on GABA(A) receptors: from protein structure to mouse behavior

This article represents the proceedings of a symposium at the 2000 ISBRA Meeting in Yokohama, Japan. The chairs were R. Adron Harris and Susumu Ueno. The presentations were (1) Protein kinase Cepsilon-regulated sensitivity of gamma-aminobutyric acid type A (GABAA) receptors to allosteric agonists, by Robert O. Messing, A. M. Sanchez-Perez, C. W. Hodge, T. McMahon, D. Wang, K. K. Mehmert, S. P. Kelley, A. Haywood, and M. F. Olive; (2) Genetic and functional analysis of a GABAA receptor gamma2 subunit variant: A candidate for quantitative trait loci involved in alcohol sensitivity and withdrawal, by Kari J. Buck and Heather M. Hood; (3) Tryptophan-scanning mutagenesis in GABAA receptor subunits: Channel gating and alcohol actions, by Susumu Ueno; and (4) Can a single binding site account for actions of alcohols on GABAA and glycine receptors? by R. Adron Harris, Yuri Blednov, Geoffrey Findlay, and Maria Paola Mascia.

Diagnosis of gram negative, ventilator associated pneumonia by assaying endotoxin in bronchial lavage fluid

AIM

To investigate the usefulness of assaying endotoxin in non-directed bronchial lavage fluid (NBL), bronchoscopic bronchoalveolar lavage fluid (BAL), and sera as a means of diagnosing Gram negative, ventilator associated pneumonia.

METHODS

Samples from 64 patients were investigated. Fifty nine BALs and 92 NBLs were assayed in total including specimens taken during 28 episodes of clinical ventilator associated pneumonia (VAP).

RESULTS

The concentration of endotoxin in BAL from patients with VAP developing within four days of commencing ventilation was significantly higher than in those without VAP (p = 0.015). There was no significant difference in endotoxin concentration in NBL or serum when comparing patients with and without VAP. A BAL endotoxin concentration of 6 EU/ml yielded the optimal operating characteristics (sensitivity, 81%; specificity, 87%; positive predictive value, 67%; negative predictive value, 95%). However, Gram stain of BAL provided the same information as quickly as the endotoxin assay and is considerably cheaper.

CONCLUSIONS

Despite its accuracy and rapidity, the BAL endotoxin assay must be shown to alter clinical management and patient outcome to be cost effective.

Blood volume determination by the carbon monoxide method using a new delivery system: accuracy in critically ill humans and precision in an animal model

OBJECTIVE

To evaluate accuracy and repeatability of blood volume determinations made by the carbon monoxide method, using a ventilator-driven administration system.

DESIGN

Prospective within-patient comparison, using simultaneous measurements by two methods to determine accuracy. Prospective laboratory investigation in animals to estimate repeatability.

SUBJECTS

For accuracy: Nineteen ventilated critically ill patients in a university hospital intensive care unit. For repeatability: Six anesthetized, mechanically ventilated normovolemic pigs because this is impossible to perform in humans.

INTERVENTIONS

In the accuracy study, a small mass of carbon monoxide was administered via a closed breathing system and arterial blood samples were taken from existing cannulas. In the repeatability study, an intramuscular sedative was given, followed by an inhalational anesthetic induction and mechanical ventilation via a tracheal tube. Left axillary artery and external jugular vein cannulas were sited. Anesthesia was maintained using an intravenous infusion. Five sequential circulating hemoglobin and blood volume estimations were made using the carbon monoxide method.

MEASUREMENTS AND MAIN RESULTS

The small carboxyhemoglobin increase produced by uptake of a small, known mass of carbon monoxide was used to estimate the circulating blood volume. Simultaneous measurement, using 51Cr-labeled red blood cells, was performed. Twenty measurements were made in 19 patients. The bias (mean difference between blood volume measurements by the two methods) was 397 mL (5.53 mL x kg(-1)) +/-415 mL (+/-5.95 mL x kg(-1)); the limits of agreement (mean difference +/-2 SD) were -433 mL and 1227 mL (-6.36 mL x kg(-1) and 17.42 mL x kg(-1)). Therefore, 95% of expected differences will lie between these limits. The mean blood volume was 75.8 mL x kg(-1) in the animals. The coefficient of variation of repeated estimates was 9.49%. Mean circulating hemoglobin mass was 7.31 mmol with a coefficient of variation of 10.18%. The mean hemoglobin concentration, by co-oximetry, was 5.014 mmol x L(-1), coefficient of variation, 2.99%.

CONCLUSION

This arrangement is a potential bedside method of estimating blood volume and circulating hemoglobin mass. We have rendered the technique more acceptable clinically by creating a ventilator-driven administration system.

Toxic shock syndrome secondary to a dental abscess

A 9-year-old girl presented with arthralgia and myalgia which progressed to developing renal failure and overwhelming septic shock. The underlying cause was assumed to be a periodontal abscess from an upper right deciduous canine tooth. The pus from the abscess grew a toxic shock syndrome toxin 1-producing Staphylococcus aureus. This case illustrates the importance of an oral surgical review of patients presenting with features of toxic shock syndrome if the source of the infection is not immediately obvious.

Splenic rupture following cardiopulmonary resuscitation

Cardiopulmonary resuscitation has improved outcome from cardiac arrest. However complications may occur secondary to the resuscitation efforts. We present a case of intraabdominal haemorrhage, due to traumatic rupture of the spleen and discuss the problems of diagnosing intraabdominal haemorrhage in the post cardiac arrest patient, whose hypotension may be ascribed to myocardial dysfunction.

A prospective study of "undiagnosed" isolated myelopathy: I. Case selection and clinical features

We aimed to carry out a study of isolated, unexplained myelopathy which avoided as far as possible selection and referral bias. We used a prospective design with case ascertainment from both neurological and neurosurgical referrals. We wanted to establish the sensitivity, predictive value and possible redundancy of currently available tests as assessed by the proportion of such patients who finally developed clinically definite multiple sclerosis at follow up. Although MRI scanning of the spinal cord is now the investigation of choice for myelopathy, the case ascertainment for the present studies was completed, and follow-up commenced, before MRI became available to patients in our catchment region. We believe that this was an important factor in the ascertainment of a representative sample of undiagnosed myelopathies. Of 2104 patients having myelography in a 36-month period, 473 had signs of a myelopathy without lower motor neurone involvement Sixty-nine of these 473 patients (15%, 95% CI 11.8-18.2) eventually satisfied the entry criteria for the prospective trial. Fourteen of the 69 patients (20%) presented with acute or subacute cord syndromes, while 55 (80%) had chronic symptoms of more than 3 months duration. Approximately two-thirds of the chronic cases were progressive and one-third relapsing and remitting. Overall there was a female predominance (3:2) and a significant excess of HLA-DR2 antigen compared with a healthy control population (p < 0.0001). In this series the patients with chronic unexplained myelopathy were younger and had shorter symptom durations (mean 46.5 months) and less disability (mean EDSS 3.0) than cases in other comparable published series. The neurological findings, sex distribution and HLA characteristics were similar to those found in patients with clinically definite MS.

The Genetic Mosaic

Blaschko's lines are the acknowledged markers which represent the patterns of systematized naevi. Their interpretation has remained mysterious, because certain special features which they exhibit are impossible to reconcile with any known anatomical system in the human body. It is proposed that by changing one's views on the nature and growth of the dermatome, the patterns of zoster, and the behaviour of tissue mosaicism, the major difficulties hitherto experienced will be overcome.

Congenital Horner syndrome associated with non-cervical neuroblastoma

Horner syndrome may be caused by a neuroblastoma involving the cervical sympathetic nervous system. A two-year-old girl presented with Horner syndrome and a discrete, distant neuroblastoma, suggesting that these two conditions represent a more widespread dysgenesis of the sympathetic nervous system.

Recovery of vision following treatment of pituitary tumours; application of a new system of assessment to patients treated by transsphenoidal operation

The lack of a standard quantitative method of assessing the degree of visual deficit hinders comparison of the results of the different methods available for treating visual failure due to a pituitary tumour. This report describes a simple, semi-quantitative, and precise approach, and illustrates its use in 34 patients treated by transsphenoidal hypophysectomy and radiotherapy. Visual improvement occurred in 85%, and no patient sustained deterioration of vision. Visual loss before operation was scored at a mean of 51.4%, and was reduced to a mean of 27.4% after a minimum of 12 months follow-up. The factor that had the greatest influence on visual recovery was the degree of visual loss at presentation. It is therefore essential to be able to compare this variable before attempting to assess if outcome is different in patients treated by different methods.