Feasibility of perioperative volatile organic compound breath testing for prediction of paralytic ileus following laparoscopic colorectal resection.

BACKGROUND: Despite implementation of enhanced recovery after surgery (ERAS) and laparoscopic techniques, postoperative ileus (POI) remains frequent after colorectal surgery, impacting the patient, their recovery and health-care resources. Presently there are no tests that reliably predict or enable early POI diagnosis. Volatile organic compounds (VC) are products of human and microbiota cellular metabolism and we hypothesised that a detectable alteration occurs in POI. METHOD: This was a prospective observational study of patients undergoing laparoscopic colorectal resection within an established ERAS programme. Standardized end-expiratory breath sampling was performed on the morning of surgery and on the first three postoperative mornings. The concentrations of VCs commonly found in intestinal gas were analysed using selected ion flow tube mass spectrometry and GastroCH4 ECK®. Feasibility data, bowel preparation, postoperative oral intake, POI and 30-day morbidity were recorded. RESULTS: Of the 75 potentially eligible patients, 58 (77%) agreed to participate. Per-protocol breath sampling was successfully completed in 94%. There were no analytical failures. Baseline and postoperative concentrations of VCs were broadly comparable and were not altered by bowel preparation or postoperative oral intake. POI developed in 14 (29%) patients. Preoperative ammonia concentration was higher in patients who developed POI [830 parts per billion (ppb) vs 510 ppb, P = 0.027]. There was an increase in the concentration of acetic acid detected on day 2 in patients who developed POI (99 ppb vs 171 ppb, P = 0.021). CONCLUSION: Repeated VC breath sampling and analysis is feasible in the perioperative setting. An elevated ammonia concentration on the morning of surgery may be a potential predictor of POI.

Artificial Neural Network Individualised Prediction of Time to Colorectal Cancer Surgery.

AIM: Colorectal cancer pathway targets mandate prompt treatment although practicalities may mean patients wait for surgery. This variable period could be utilised for patient optimisation; however, there is currently no reliable predictive system for time to surgery. If individualised surgical waits were prospectively known, tailored prehabilitation could be introduced. METHODS: A dedicated, prospectively populated elective laparoscopic surgery for colorectal cancer with a curative intent database was utilised. Primary endpoint was the prediction of the individualised waiting time for surgery. A multilayered perceptron artificial neural network (ANN) model was trained and tested alongside uni- and multivariate analyses. RESULTS: 668 consecutive patients were included. 8.5% underwent neoadjuvant chemoradiotherapy. The mean time from diagnosis to surgery was 53 days (95% CI 48.3-57.8). ANN correctly identified those having surgery in <8 (97.7% and 98.8%) and <12 weeks (97.1% and 98.8%) of the training and testing cohorts with area under the receiver operating curves of 0.793 and 0.865, respectively. After neoadjuvant treatment, an ASA physical status score was the most important potentially modifiable risk factor for prolonged waits (normalised importance 64%, OR 4.9, 95% CI 1.5-16). The ANN findings were accurately cross-validated with a logistic regression model. CONCLUSION: Artificial neural networks using demographic and diagnostic data successfully predict individual time to colorectal cancer surgery. This could assist the personalisation of preoperative care including the incorporation of prehabilitation interventions.

2D versus 3D laparoscopic total mesorectal excision: a developmental multicentre randomised controlled trial.

AIMS: The role of laparoscopy in rectal cancer has been questioned. 3D laparoscopic systems are suggested to aid optimal surgical performance but have not been evaluated in advanced procedures. We hypothesised that stereoscopic imaging could improve the performance of laparoscopic total mesorectal excision (TME). METHODS: A multicentre developmental randomised controlled trial comparing 2D and 3D laparoscopic TME was performed (ISRCTN59485808). Trial surgeons were colorectal consultants that had completed their TME proficiency curve and underwent stereoscopic visual testing. Patients requiring elective laparoscopic TME with curative intent were centrally randomised (1:1) to 2D or 3D using Karl Storz IMAGE1 S D3-Link™ and 10-mm TIPCAM®1S 3D passive polarising laparoscopic systems. Outcomes were enacted adverse events as assessed by the observational clinical human reliability analysis technique, intraoperative data, 30-day patient outcomes, histopathological specimen assessment and surgeon cognitive load. RESULTS: 88 patients were included. There were no differences in patient or tumour demographics, surgeon stereopsis, case difficulty, cognitive load, operative time, blood loss or conversion between the trial arms. 1377 intraoperative adverse events were identified (median 18 per case, IQR 14-21, range 2-49) with no differences seen between the 2D and 3D arms (18 (95% CI 17-21) vs. 17 (95% CI 16-19), p = 0.437). 3D laparoscopy had non-significantly higher mesorectal fascial plane resections (94 vs. 77%, p = 0.059; OR 0.23 (95% CI 0.05-1.16)) but equal lymph node yield and circumferential margin distance and involvement. 30-day morbidity, anastomotic leak, re-operation, length of stay and readmission rates were equal between the 2D and 3D arms. CONCLUSION: Feasibility of performing multicentre 3D laparoscopic multicentre trials of specialist performed complex procedures is shown. 3D imaging did not alter the number of intraoperative adverse events; however, a potential improvement in mesorectal specimen quality was observed and should form the focus of future 3D laparoscopic TME trials.

Closure of the perineal defect after abdominoperineal excision for rectal adenocarcinoma - ACPGBI Position Statement.

BACKGROUND: Perineal wound morbidity is common following abdominoperineal excision of the rectum (APE). There is no consensus on the optimum perineal reconstruction method after APE, and in particular 'extra-levator APE' (ELAPE). METHODS: A systematic review of the PubMed, Embase and Cochrane databases was performed. This position statement formulated clinical questions and graded the evidence to make recommendations. RESULTS: Perineal wound complications may be higher following ELAPE compared to 'conventional APE (cAPE)' however there is insufficient evidence to recommend cAPE over ELAPE with regards to the impact upon perineal wound healing. The majority of cAPE studies have used primary closure with varying complication rates reported. Where concerns regarding perineal wound healing exist, myocutaneous flap closure may be considered as an alternative method. There is minimal available evidence on perineal mesh reconstruction following cAPE. Primary closure, mesh use and myocutaneous flap reconstruction following ELAPE has been reported although variations in definitions and low-quality of available evidence limit comparison. There is insufficient evidence to recommend one particular method of perineal closure after ELAPE. Primary perineal closure is likely to have a higher risk of perineal herniation. Myocutaneous flaps and biological mesh have been effectively used in ELAPE closure. There is insufficient evidence to support one particular type of flap or mesh. Perineal wound complication rates are significantly increased when neo-adjuvant radiotherapy is delivered, regardless of surgical technique. There is no evidence that laparoscopy reduces APE perineal wound complications. CONCLUSION: This position statement updates clinicians on current evidence around perineal closure after APE surgery.

Time from colorectal cancer diagnosis to laparoscopic curative surgery-is there a safe window for prehabilitation?

BACKGROUND: There is a growing interest in the adoption of formal prehabilitation programmes prior to elective surgery but regulatory targets mandate prompt treatment following cancer diagnosis. We aimed to investigate if time from diagnosis to surgery is linked to short- and long-term outcomes. METHODS: An exploratory analysis was performed utilising a dedicated, prospectively populated database. Inclusion criteria were biopsy-proven colorectal adenocarcinoma undergoing elective laparoscopic surgery with curative intent. Demographics, date of diagnosis and surgery was captured with patients dichotomised using 4-, 8- and 12-week time points. All patients were followed in a standardised pathway for 5 years. Overall survival was assessed with the Kaplan-Meier log-rank method. RESULTS: Six hundred sixty-eight consecutive patients met inclusion criteria. Mean time from diagnosis to surgery was 53 days (95% CI 48.3-57.8). Identified risk factors for longer time to surgery were males (OR 1.92 [1.2-3.1], p = 0.008), age ≤ 65 (OR 1.9 [1.2-3], p = 0.01), higher ASA scores (p = 0.01) stoma formation (OR 6.9 [4.1-11], p < 0.001) and neoadjuvant treatment (OR 5.06 [3.1-8.3], p < 0.001). There was no association between time to surgery and BMI (p = 0.36), conversion (16.3%, p = 0.5), length of stay (p = 0.33) and readmission or reoperation (p = 0.3). No differences in five-year survival were seen in those operated within 4, 8 and 12 weeks (p = 0.397, p = 0.962 and p = 0.611, respectively). Multivariate analysis showed time from diagnosis to surgery was not associated with five-year overall survival (HR 0.99, p = 0.52). CONCLUSION: Time from colorectal cancer diagnosis to curative laparoscopic surgery did not impact on overall survival. This finding may allow preoperative pathway alteration without compromising safety.

EAES classification of intraoperative adverse events in laparoscopic surgery.

BACKGROUND: Surgical outcomes are traditionally evaluated by post-operative data such as histopathology and morbidity. Although these outcomes are reported using accepted systems, their ability to influence operative performance is limited by their retrospective application. Interest in direct measurement of intraoperative events is growing but no available systems applicable to routine practice exist. We aimed to develop a structured, practical method to report intraoperative adverse events enacted during minimal access surgical procedures. METHODS: A structured mixed methodology approach was adopted. Current intraoperative adverse event reporting practices and desirable system characteristics were sought through a survey of the EAES executive. The observational clinical human reliability analysis method was applied to a series of laparoscopic total mesorectal excision (TME) case videos to identify intraoperative adverse events. In keeping with survey results, observed events were further categorised into non-consequential and consequential, which were further subdivided into four levels based upon the principle of therapy required to correct the event. A second survey phase explored usability, acceptability, face and content validity of the novel classification. RESULTS: 217 h of TME surgery were analysed to develop and continually refine the five-point hierarchical structure. 34 EAES expert surgeons (69%) responded. The lack of an accepted system was the main barrier to routine reporting. Simplicity, reproducibility and clinical utility were identified as essential requirements. The observed distribution of intraoperative adverse events was 60.1% grade I (non-consequential), 37.1% grade II (minor corrective action), 2.4% grade III (major correction or change in post-operative care) and 0.1% grade IV (life threatening). 84% agreed with the proposed classification (Likert scale 4.04) and 92% felt it was applicable to their practice and incorporated all desirable characteristics. CONCLUSION: A clinically applicable intraoperative adverse event classification, which is acceptable to expert surgeons, is reported and complements the objective assessment of minimal access surgical performance.

Can the combination of laparoscopy and enhanced recovery improve long-term survival after elective colorectal cancer surgery?

AIM: Enhanced recovery after surgery (ERAS) programmes and laparoscopic techniques both provide short-term benefits to patients undergoing colorectal cancer surgery. ERAS protocol compliance may improve long-term survival in those undergoing open colorectal resection but as laparoscopic data has not been reported. Therefore, we aimed to investigate the impact of the combination of laparoscopy and ERAS management on 5-year overall survival. METHODS: A dedicated prospectively populated colorectal cancer surgery database was reviewed. Patient inclusion criteria were biopsy-proven colorectal adenocarcinoma, undergoing elective surgery undertaken with curative intent. All patients were managed within an established ERAS programme and routinely followed up for 5 years. Overall survival was measured using the log-rank Kaplan-Meier method at 5 years. RESULTS: Eight hundred fifty-four patients met the inclusion criteria. Four hundred eighty-one (56%) cases were laparoscopic with 98 patients (20%) requiring conversion. There were no differences in patient or tumour demographics between the surgical groups. Median ERAS protocol compliance was 93% (range 53-100%). Five-year overall survival was superior in laparoscopic cases compared with that of converted and open surgery (78 vs 68 vs 70%, respectively, p < 0.007). An open approach (HR 1.55, 95%CI 1.16-2.06, p = 0.002) and delayed hospital discharge (> 7 days, HR 1.5, 95%CI 1.13-1.9, p = 0.003) were the only modifiable risk factors associated with poor survival. CONCLUSIONS: The use of a laparoscopic approach with enhanced recovery after surgery management appears to have long-term survival benefits following colorectal cancer resection.

Developing a national colorectal educational agenda: a survey of the Association of Coloproctology of Great Britain and Ireland.

AIM: In order to develop its education agenda, the Association of Coloproctology of Great Britain and Ireland (ACPGBI) sought the opinion of its members on current coloproctology training needs. The aims of this study were to canvass multidisciplinary needs and explore the perceived gaps and barriers to meeting them. METHOD: A learner-needs analysis was performed between July 2015 and October 2016. A bespoke electronic survey was sent to 1453 colorectal healthcare professionals [ACPGBI membership (1173), colorectal nurse specialists and allied health professionals (NAHPs) (261) and regional chapter-leads (19)] seeking their needs, experiences and barriers to training across the coloproctology disciplines. RESULTS: In all, 390 responses were received [26.8% overall; 180 consultants/trainees (15%); 196 NAHPs (75%); 14 (74%) chapter-leads]. Lack of funding and difficulties in obtaining study leave were the most frequently reported barriers to course and conference attendance. Transanal total mesorectal excision and laparoscopic training were the top educational needs for consultants and trainees respectively. 79% of NAHP respondents reported education gaps on a broad range of clinical and non-clinical topics. NAHPs lacked information on relevant training opportunities and 27% felt available courses were insufficient to meet their educational needs. Wide heterogeneity in ACPGBI chapter composition and activity was reported. All groups felt the ACPGBI should increase the number of courses offered with coloproctology knowledge updates commonly requested. CONCLUSION: A series of training needs across the coloproctology disciplines have been identified. These will underpin the development of the educational agenda for the ACPGBI.

Objective assessment of minimally invasive total mesorectal excision performance: a systematic review.

INTRODUCTION: Laparoscopy is widely used in colorectal practice, but recent trial results have questioned its use in rectal cancer resections. Patient outcomes are directly linked to the quality of total mesorectal excision (TME) specimen. Objective assessment of intraoperative performance could help ensure competence and delivery of optimal outcomes. Objective tools may also contribute to TME intervention trials, but their nature, structure and utilisation is unknown. AIM: To systemically review the available literature to report on the available tools for the objective assessment of minimally invasive TME operative performance and their use within multicentre laparoscopic TME randomised controlled trials. METHODS: A systematic search of the PubMed and Cochrane databases was performed to identify tools used in the objective intraoperative assessment of minimally invasive TME performance in accordance with the PRISMA guidelines, independently by two authors. The identified tools were then evaluated within reported TME RCTs. RESULTS: A total of 8642 abstracts were screened of which 12 papers met the inclusion criteria; ten prospective observational studies, one randomised trial and one educational consensus. Eight assessment methods were described, which include formative and summative tools. The tools were mostly adaptations of colonic surgery tools based on either operative video review or post-operative trainer rating. All studies reported objective assessment of intraoperative performance was feasible, but only 126 (7%) of the 1762 included laparoscopic cases were TME. No multicentre laparoscopic TME trial reported using any objective surgical performance assessment tool. CONCLUSION: Objective intraoperative laparoscopic TME performance assessment is feasible, but most of the current tools are adaptation of colonic surgery. There is a need to develop dedicated assessment tools for minimal access rectal surgery. No multicentre minimally invasive TME RCT reported using any objective assessment tool.

Does hospital readmission following colorectal cancer resection and enhanced recovery after surgery affect long term survival?

AIM: Hospital readmission is undesirable for patients and care providers as this can affect short-term recovery and carries financial consequences. It is unknown if readmission has long-term implications. We aimed to investigate the impact of 30-day readmission on long-term overall survival (OS) following colorectal cancer resection within enhanced recovery after surgery (ERAS) care and explore the reasons for and the severity and details of readmission episodes. METHOD: A dedicated, prospectively populated database was reviewed. All patients were managed within an established ERAS programme. Five-year OS was calculated using the Kaplan-Meier method. The number, reason for and severity of 30-day readmissions were classified according to the Clavien-Dindo (CD) system, along with total (initial and readmission) length of stay (LoS). Multivariate analysis was used to identify factors predicting readmission. RESULTS: A total of 1023 consecutive patients underwent colorectal cancer resection between 2002 and 2015. Of these, 166 (16%) were readmitted. Readmission alone did not have a significant impact on 5-year OS (59% vs 70%, P = 0.092), but OS was worse in patients with longer total LoS (20 vs 14 days, P = 0.04). Of the readmissions, 121 (73%) were minor (CD I-II) and 27 (16%) required an intervention of which 16 (10%) were returned to theatre. Gut dysfunction 32 (19%) and wound complications 23 (14%) were the most frequent reasons for readmission. Prolonged initial LoS, rectal cancer and younger age predicted for hospital readmission. CONCLUSION: Readmission does not have a significant impact on 5-year OS. A broad range of conditions led to readmission, with the majority representing minor complications.

Is Month of Birth a Risk Factor for Colorectal Cancer?

Introduction. The developmental origins of health and disease hypothesis and season of birth have been linked to a wide variety of later life conditions including cancer. Whether any relationship between month and season of birth and colorectal cancer exists is unknown. Methods. A case-control study was performed with month of birth extracted from a dedicated colorectal cancer database. Age and gender matched patients were used as a control group. Generalised linear models were fitted with Poisson and negative binomial responses and logarithmic links. A forward stepwise approach was followed adding seasonal components with 6- and 12-month periods. Results. 1019 colorectal cancer patients and 1277 randomly selected age and gender matched controls were included. For both men and women there is an excess of colorectal cancer in those born in autumn and a corresponding reduction of risk among those born in spring (p = 0.026). For the identified September peak, the excess risk for colorectal cancer was 14.8% (95% CI 5.6-32.3%) larger than the spring trough. Conclusion. There is a seasonal effect in the monthly birth rates of people who are operated for colorectal cancer with a disproportionate excess of cancer in those born in September. Further large studies are required to validate these findings.

Single hospital visit elective day-case laparoscopic cholecystectomy without prior outpatient attendance.

INTRODUCTION: Eighty percent of all UK elective laparoscopic cholecystectomies (LC) are performed as day-case procedures, but the pre-operative patient pathway has received little attention. In response to local patient feedback, we aimed to introduce a single hospital visit pathway for day-case LC. METHODS: A single hospital visit pathway for elective LC was piloted alongside standard services. Following telephone consultation, a pack containing procedure information, knowledge questionnaire and consent form were sent. Patients were not excluded on age, BMI or co-morbidity criteria, but recent ultrasonography and liver function tests were required. Patients were operated without attending any clinic or pre-operative service. There was no restriction on surgical or anaesthetic technique. Early surgeon-led telephone follow-up was made post-operatively and patient satisfaction assessed at 3 months. RESULTS: One hundred and sixty-six patients were referred with 92% transferred to day-case waiting lists following telephone consultation. One hundred and six patients underwent LC without previously visiting the hospital with 85% discharged the same day. Nine percent required post-operative primary care review primarily for wound reviews. Median patient-reported time to normal activities was 4 weeks (range 1-12). Ninety-nine percent reported being satisfied with the single-stop pathway. CONCLUSIONS: Single hospital visit LC is feasible, safe and acceptable for primary care referral patients with symptomatic gallstone disease without evidence of common bile duct or LFT abnormalities.

Single hospital visit day case laparoscopic hernia repair without prior outpatient consultation is safe and acceptable to patients.

BACKGROUND: For some common conditions, pre-operative clinic visits are often of little value to the patient or surgeon with transfer to the waiting list being predictable. In response to local patient feedback, we introduced a single hospital visit laparoscopic hernia surgery pathway with focus on informed consent, patient-reported outcomes and post-operative interaction with primary care services. METHODS: A single hospital visit service for elective hernia repairs was created. Patients were not excluded on age, BMI or co-morbidity. Following referral, patients were telephoned by a surgeon. If considered appropriate, a symptom assessment tool, procedure information and consent form were sent. All patients were operated without attending clinic or pre-operative assessment. Surgeon-led telephone follow-up was made at either 2 or 7 days post-operatively and patient satisfaction assessed at 3 months. RESULTS: A total of 517 patients were referred for single-stop surgery between 2012 and 2015. Median age was 58 (range 20-92), 91 % were male, and mean BMI was 25.6 (17.4-52.0). No patient refused the single-visit pathway. Single-stop patients had higher knowledge questionnaire scores (mean 16 vs. 10, p = 0.01) than patients who had attended clinic. Nine (1.7 %) were requested to attend clinic to confirm diagnosis, and three (0.8 %) were cancelled by their surgeon on the operative day. A total of 393 hernia repairs (331 TEP, 63 open) were performed under general anaesthetic. 92 % were discharged on day zero. Telephone follow-up day two rather than seven decreased attendance to primary care services (25 % vs. 57 %, p = 0.001). At 3 months, 95 % were satisfied and symptom scores were reduced (median 5-0, p < 0.0001). CONCLUSION: Single-visit surgery appears to extend the patient benefits of laparoscopy by reducing hospital visits without compromising safety. Single hospital visit hernia surgery for unselected primary care referrals is possible and acceptable to patients.

The adaptive immune response to colorectal cancer: from the laboratory to clinical practice.

INTRODUCTION: Analysis of the adaptive immune system in the microenvironment of colorectal cancer is suggested to offer new insights into tumour biology and prognostic information independent of TNM staging. We aimed to review recent findings to investigate the potential for clinical use. METHODS: Relevant papers were identified through online searches regarding tumour infiltrating lymphocytes (TIL) in colorectal cancer. Identified papers were studied, focusing on clinically applicable uses for TIL data in the management of colorectal cancer. FINDINGS: The majority of identified studies were retrospective and observational in nature. The widest TIL investigation was in post resection prognosis but TIL subtypes, counts and methodology showed variability between studies. Recent reports explored TIL in predicting response to adjuvant and neoadjuvant treatments. CONCLUSION: An increasing body of evidence supports that visibility of colorectal cancer to immune attack is substantial and that it limits disease progression. Analysis of the adaptive immune infiltrate in resected colorectal cancer specimens offers prognostic information which is independent of conventionally measured parameters and potentially superior in predictive value.

Acute radiation enteritis causing small bowel obstruction.

Although much is known about the late intestinal side effects of radiation, comparatively little has been published about its acute complications. We present a case of a small bowel obstruction due to acute radiation enteritis. As radiotherapy continues to expand its role in the management of oncological disease, clinicians should remain alert to the resulting undesired effects.

A case of aggressive multiple metachronous central giant cell granulomas of the jaws: differential diagnosis and management options.

We describe multiple metachronous central giant cell granulomas in a 62-year-old man who has a first degree relative with a history of a solitary central giant cell granulomas. The patient presented in 1997 with a large central giant cell granuloma of the right maxilla which was treated with a partial maxillectomy. A small recurrence was then identified and the successful management of this is described. The patient has also a histologically confirmed central giant cell granuloma previously removed from the right body of the mandible and the left angle of the mandible. The differential diagnosis of multiple central giant cell granulomas of the jaw is considered. It is possible that the present case may indeed represent a new syndrome or subtype of multiple central giant cell granulomas. The problem of treating such aggressive sub-types of giant cell granulomas is also addressed in the context of recent advances of surgical and medical management.

Morphology of the pupal heart, adult heart, and associated tissues in the fruit fly, Drosophila melanogaster.

The early pupal heart of the fruit fly Drosophila melanogaster has recently been the subject of intense physiological and molecular work, yet it has not been well described, nor has it been compared with the heart of the adult fly. In the work reported here, the hearts of adults and early pupae of D. melanogaster were studied by scanning and transmission electron microscopy and by light microscopy. The hearts of adults and early pupae both consist of a tube of circular striated muscle one cell in thickness. The alary muscles, which suspend the heart, are more delicate in the adult compared to the early pupa. The pericardial cells in both early pupae and adults are connected to the heart by connective tissue radiating from the alary muscles or dorsal diaphragm. We confirm that four major changes occur in the heart during metamorphosis: 1) a conical chamber is formed de novo in the first and second abdominal segments; 2) the adult heart curves to conform to the contour of the abdomen; 3) a layer of longitudinal striated muscle appears on the ventral surface of the heart; 4) a fourth pair of ostia is added to the three already present in the early pupa; and note additionally that 5) the ostia appear as simple openings in the heart of the early pupa but are valve-like in the adult.

Preliminary study of microsurgical repairs of the inferior alveolar nerve in rats using primary suturing and laser weld techniques.

A comparison of primary suturing and a new laser weld technique is described for the microsurgical repair of the inferior alveolar nerve in Wistar rats. A reliable method of exposure of the inferior alveolar nerve has been developed in order to allow intraosseous repairs of the nerve involving suturing with 10:0 nylon and a laser weld technique using an albumin-based solder, containing indocynine cardiogreen, plus an infrared (810 nm wavelength) diode laser. Seven cases of microsuture and laser weld repairs were performed with a 29.4% reduction in total operating time in the laser weld group. Histochemical analysis showed comparable mean neuron counts and mean tracer uptake by neurons for the microsuture and laser weld groups. Giant cell reactions were identified in two of the primary suture cases and axon deflection in three cases demonstrating possible advantages of the laser weld technique which showed no adverse reactions by axons or epineurium to the coagulative repair with the solder. The technique of laser weld repair, on initial analysis, therefore appears comparable with traditional suture repairs and indeed may possess several advantages. Further studies are recommended.

Intraosseous repair of the inferior alveolar nerve in rats: an experimental model.

A reliable method of exposure of the inferior alveolar nerve in Wistar rats has been developed, to allow intraosseous repair with two microsurgical techniques under halothane inhalational anaesthesia. The microsuturing technique involves anastomosis with 10-0 nylon sutures; a laser-weld technique uses an albumin-based solder containing indocyanine green, plus an infrared (810 nm wavelength) diode laser Seven animals had left inferior alveolar nerve repairs performed with the microsuture and laser-weld techniques. Controls were provided by unoperated nerves in the repaired cases. Histochemical analysis was performed utilizing neuron counts and horseradish peroxidase tracer (HRP) uptake in the mandibular division of the trigeminal ganglion, following sacrifice and staining of frozen sections with cresyl violet and diaminobenzidene. The results of this analysis showed similar mean neuron counts and mean HRP uptake by neurons for the unoperated controls and both microsuture and laser-weld groups. This new technique of intraosseous exposure of the inferior alveolar nerve in rats is described. It allows reliable and reproducible microsurgical repairs using both microsuture and laser-weld techniques.