OC-054 LONG-TERM OUTCOMES OF POSTERIOR COMPONENT SEPARATION WITH TRANSVERSUS ABDOMINIS RELEASE (TAR) IN LARGE AND OTHER COMPLEX VENTRAL HERNIAS: A SINGLE-SURGEON EXPERIENCE

Aim

The application of component separation techniques for the repair of large and other complex ventral hernias, has been a landmark in their successful management. The aim of this study is to present our experience with the posterior component separation with transversus abdominis release (TAR) in patients with these very demanding ventral hernias.

Material & Methods

A retrospective analysis of prospectively collected data of all patients who underwent elective ventral hernia repair with TAR technique between January 2016 and May 2021 was performed. Selection of the type of inserted mesh was based on the risk of developing surgical site infection (SSI) and other surgical site occurrences (SSOs). Preoperative, intraoperative, and postoperative data were analyzed.

Results

A total of 167 patients with large and other complex ventral hernias were included in the final analysis. More than 80% of patients had one or more comorbidities. Of all patients, 156 (93.4%) had a history of previous abdominal surgery, 42 (25.1%) had a history of SSI and 11 (6.6%) had active fistulas, of which nine involved previous implanted meshes. Postoperatively, SSOs were presented in 12 patients (7.2%), including three cases of SSI. Neither mesh infection occurred, nor mesh excision required. With a mean follow-up of 3 years, only one recurrence has been observed.

Conclusions

With a wound complication rate of less than 8% and a recurrence rate of less than 1%, our results show that TAR is a reliable, safe and effective technique for the repair of large and other complex ventral hernias.

Intramedullary nailing of trochanteric fractures: central or caudal positioning of the load carrier? A biomechanical comparative study on cadaver bones

BACKGROUND

Current recommendations with regard to central or caudal positioning of the femur head carrier in the management of trochanteric fractures are contradictory.

METHODS

A standardised pertrochanteric osteotomy was stabilised in 15 pairs of cadaver femurs by means of intramedullary osteosynthesis (5xPFN-A-Synthes, 5xIntertan-Smith&Nephew, 5xTargon-PF-Aesculap). For each pair randomised central (group A) or caudal (group B) implantation of the femoral neck component was performed. Subsequently, the constructs were axially loaded to 2100N. In the absence of cut out after 20,000 cycles, load was increased to a maximum force of 3100N. Angular displacement was recorded based on ultrasound. Migration of the load carrier in the femoral head was monitored radiologically.

FINDINGS DISPLACEMENT

No significant difference between groups (p>0.15) was found for the first 50 load cycles. A significantly greater degree of varus deformity was observed in group A (p=0.049) after 2000 load cycles and became more apparent as the number of load cycles increased (after 6000 cycles p=0.039, after 20,000 cycles p=0.034, after 22,000 cycles p=0.016). Angular displacement in the other two planes did not differ significantly across groups. CUT OUT: Migration of the load carrier in the femoral head was not significantly different for the two groups. Overall cut out occurred in 9 constructs, 3 in group A and 6 in group B. The difference in cut-out rate was not significant (p=0.213, chi-squared test).

CONCLUSION

Biomechanical superiority can be shown for caudal positioning of the femoral neck load carrier in terms of reduced varus deformity. The incidence of cut out is however unaffected by the position of the load carrier.

Complicated liver echinococcosis: 30 years of experience from an endemic area

BACKGROUND AND AIMS

Although declining, cystic echinococcosis is still a serious public health issue in Greece. This study evaluated the clinical features, management, and short-term outcome of patients with complicated liver echinococcosis.

MATERIAL AND METHODS

A total of 227 patients who were operated on for 322 echinococcal cysts of the liver were retrospectively evaluated. Patients were divided into those with complicated disease (53.7%) and those with noncomplicated disease (46.3%). Intrabiliary rupture (34.4%), cyst infection (32.7%), and their combination (24.5%) were the most common complications. Demographic characteristics, previous hydatid cyst surgery, cyst multiplicity and location, presenting symptoms and signs, types of complicated disease, operative procedures performed, postoperative complications, and hospital stay were assessed.

RESULTS

Patient demographics and cyst characteristics demonstrated no significant difference between the two groups. The complicated disease group had significantly more pronounced clinical presentations and higher postoperative morbidity. Choice of surgical procedure depended upon cyst location and surgeon preference. Both conservative and radical procedures were performed, supplemented with additional management of the biliary tree when indicated.

CONCLUSIONS

Complicated liver echinococcosis demonstrates several distinct features that differentiate it from the noncomplicated disease. Frequently severe clinical manifestations, complexity of surgical management, and the increased postoperative complications characterize complicated liver echinococcal disease.

Children and adolescents with posttraumatic shoulder instability benefit from arthroscopic stabilization

INTRODUCTION

Traumatic dislocation of the shoulder in childhood is rare, accounting for only 0.01% of all injuries in this age class. However, literature does contain indications that post-traumatic instabilities and re-dislocations occur with more than average frequency in children and adolescents.

MATERIAL AND METHODS

This study describes the technique and results of arthroscopic stabilization of the shoulder joint before the completion of growth. Over a period of four years, seven patients were treated prior to reaching skeletal maturity. Five patients were treated by means of arthroscopically assisted labral refixation using suture anchor systems.

RESULTS

Arthroscopic labral refixation for post-traumatic shoulder instability could be carried out using the same surgical procedure as in adults. Clinical follow-up was undertaken after 12 to 48 (average 26) months using modified Constant-Murley and Rowe scores. Instability, re-dislocations and postoperative impairment of mobility did not occur after arthroscopic treatment, with an average Constant score of 92 points (Rowe score >95 points).

CONCLUSION

This study demonstrated that this technique can be used successfully in children and young people prior to skeletal maturity. Considerable experience in adult shoulder reconstruction promises excellent results in children and adolescents, too. There was no evidence of growth disturbance or biodegradation-associated problems in this group of children and adolescents. Delay of labral refixation until adulthood is therefore not indicated.

Deeply infiltrating rectal endometriosis with lymph node involvement

BACKGROUND

Sigmoidorectal endometriosis accounts for 70% of the cases of intestinal endometriosis. Symptoms are non-specific, frequently resembling adenocarcinomas.

CASE

A 45-year-old woman complaining of recurrent rectal bleeding underwent colonoscopy in which a rectal polypoid mass was found. She underwent anterior rectosigmoidectomy and the histological examination of the resected bowel revealed rectal endometriosis with lymph node involvement.

CONCLUSION

Lymphatic infiltration of epicolic lymph nodes raises questions about the benign nature of this presumed innocent disease.

Unusual findings in inguinal hernia surgery: report of 6 rare cases

BACKGROUND AND AIM

To present our experience with unexpected findings during hernia surgery, either unusual hernial contents or pathologic entities, like neoplastic masses, masquerading as a hernia.

PATIENTS AND METHODS

We studied retrospectively 856 patients with inguinal hernia who were admitted to our surgical department over a 9-year period. In addition, our study included patients complaining of inguinal protrusion, even without a definitive diagnosis of inguinal hernia upon admission.

RESULTS

Five patients presented with unusual hernial contents. Three of them had a vermiform appendix in their sac. Acute appendicitis (Amyands hernia) was found in only one case. One patient had epiploic appendagitis related with a groin hernia. Moreover, an adult woman was diagnosed with ovarian and tubal inguinal hernia. Finally, we report a case of a massive extratesticular intrascrotal lipoma, initially misdiagnosed as a scrotal hernia.

CONCLUSION

a hernia surgeon may encounter unexpected intraoperative findings. It is important to be prepared to detect them and apply the appropriate treatment.

Primary Ewing sarcoma of the stomach--a newly described entity

The Ewing sarcoma family of tumors (ESFT) includes classic Ewing sarcoma of the bone, extraosseous or soft tissue Ewing sarcoma, Askin tumors of the chest wall, and peripheral primitive neuroectodermal tumors of the bone and soft tissues. They share a common neural histogenesis, tumor genetics and biology. The genetic hallmark of the ESFT is the presence of t(11;22)(q24;q12), which creates the EWS/FLI1 fusion gene and results in the expression of a chimeric protein. Although Ewing tumors can occur at any age, the great majority are found in individuals less than 20 years of age. We herein report a case of gastric Ewing sarcoma in a 68-year-old male. This patient illustrates the second reported occurrence of primary Ewing sarcoma in the stomach and the first reported with the t(11;22)(q24;q12) gene translocation.

[Elastic stable intramedullary nailing (ESIN) in pediatric forearm shaft fractures: intraoperative image intensifier times]

AIM

Elastic stable intramedullary nailing (ESIN)is the therapy of choice in pediatric forearm shaft fractures. It requires increased intraoperative image intensifier times and radiation load.

METHOD

We performed a retrospective analysis of 78 operative procedures from a five-year period. In 16 cases the image intensifier times of the distinct steps of the operation were investigated prospectively.

RESULTS

Average duration of the surgical procedure was 36.9 (18-144) minutes. Average radiation time was 59.5 (8-222) seconds. In educational operations, the duration of surgery was significantly longer than in procedures performed by experienced surgeons, but radiation times only were increased tendentially. In those procedures investigated prospectively, 53.1% of the image intensifier time was used for fracture passage.

CONCLUSION

In ESIN of forearm shaft fractures,intraoperative image intensifier times of less than 2 minutes can be expected. Low intraoperative radiation times are a mark of quality. They serve for radiation protection of the patients, surgeons and OT staff.

Validated H5 Eurasian Real-Time Reverse Transcriptase–Polymerase Chain Reaction and Its Application in H5N1 Outbreaks in 2005–2006

Real time reverse transcriptase (RRT)-polymerase chain reaction (PCR) for the detection of Eurasian H5 avian influenza virus (AIV) isolates was adapted from an existing protocol, optimized, and validated using a number of genetically diverse H5 isolates (n = 51). These included 34 "Asian lineage" H5N1 highly pathogenic avian influenza (HPAI) viruses (2004-2006), plus 12 other H5 isolates from poultry outbreaks and wild birds in the Eastern Hemisphere (1996-2005). All 51 were positive by H5 Eurasian RRT-PCR. Specificity was assessed by testing representative isolates from all other AL virus subtypes (n = 52), non-AI avian pathogens (n = 8), plus a negative population of clinical specimens derived from AI-uninfected wild birds and poultry (n = 604); all were negative by H5 Eurasian RRT-PCR. RNA was directly extracted from suspect HPAI H5N1 clinical specimens (Africa, Asia, and Europe; 2005-2006; n = 58) from dead poultry and wild birds, and 55 recorded as positive by H5 Eurasian RRT-PCR: Fifty-one of these 55 were in agreement with positive AIV isolation in embryonated chickens' eggs. H5 Eurasian RRT-PCR was invaluable in H5 outbreak diagnosis and management by virtue of its rapidity and high degree of sensitivity and specificity. This method provides a platform for automation that can be applied for large-scale intensive investigations, including surveillance.

Die Problematik der Hoffa-Fraktur

To study the outcome in Hoffa fractures regarding the type of fracture, concomitant injuries, and different treatments. From January 1996 until December 2002, 7 Hoffa fractures (6 patients) from a total of 79 distal femoral fractures were treated in the Department of Trauma Surgery, University Hospital of Giessen. The results were evaluated by Neer's score. For the evaluation of postoperative vascularization of the distal femur, clinical and radiological findings were compared with anatomical studies of the bone arteries by corrosion preparations. Fracture consolidation was seen in all cases. Patients with an isolated Hoffa fracture achieved a score of 89.0 (82-97) according to Neer. One patient suffering initially from nonunion achieved 68 points after bone union. One polytraumatized patient with bilateral Hoffa fracture achieved a satisfying result (score value of 72) and a bad result (score value of 38). Multiple small nutrient arteries of the distal femur originate from the "rete articulare genus." They can be expected to ensure the arterial blood supply. Hoffa fracture is a very rare injury. In our patients, careful surgical treatment with open reduction and safe screw fixation yielded good to very good results.

[Tenoplasty of the long head of the biceps in massive rotator cuff tear]

AIM

It was the aim of this study to investigate the success of biceps tenoplasty in massive interval rotator cuff tears.

METHOD

Fifteen patients, who had a massive rotator cuff tear in the area of the interval and a pathology of the long head of the biceps tendon, were examined clinically and by MRI. A primary reconstruction of the rotator cuff tear was possible in none of the patients. All patients had a secondary reconstruction with a biceps tenoplasty. The Constant Score was determined postoperatively and the satisfaction of the patients was explored.

RESULTS

The mean age at the time of the operation was 55 years. The examination was 23 months postoperatively. A simultaneous rupture of the supraspinatus- and subscapularis tendon was seen in 12 patients, an additional rupture of the infraspinatus tendon in 3 patients intraoperatively. The long head of the biceps was dislocated in 10 patients and subluxated in 5 patients. The postoperative determined Constant Score was 82.7 points. The personal satisfaction was investigated by asking for the German schoolmarks, which extend from 1 (excellent) to 6 (not satisfactory). The preoperative schoolmark was 5.2 and the postoperative schoolmark 1.4. In the MRI examination one rerupture could be seen, an atrophy of the supraspinatus tendon was evaluated in four patients. Knowing the postoperative result, all patients would have repeated the operation.

CONCLUSION

The biceps tenoplasty is a suitable operative method to achieve a better function and relief of pain in massive interval rotator cuff tears with simultaneous pathology of the long head of the biceps tendon. A high degree of personal satisfaction for the patient can be achieved.

Plummer-Vinson syndrome

Plummer-Vinson syndrome is characterized by dysphagia, iron deficiency, anemia and the presence of esophageal web or webs. Two cases of this syndrome are reported in middle-aged women, which were treated over the last eight years. Both patients presented with dysphagia, anemia, sideropenia, glossitis and cheilitis. Radiological examination of the pharynx showed the presence of webs in both cases. The patients were treated with iron supplementation, which resulted in elimination of the symptoms. Both patients remain in good general condition and without any dysphagic complaints, 5 and 8 years after the diagnosis, respectively.

Splenectomy versus spleen-preserving surgery for splenic echinococcosis

BACKGROUND/AIMS

The spleen is the third most common location of hydatid disease after liver and lung. The aim of this study was to analyse the long-term outcome of surgical treatment of patients with splenic echinococcosis comparing splenectomy with spleen-preserving surgery.

METHODS

During a period of 25 years (1976-2001), 19 (5.4%) patients with splenic echinococcosis were treated in our department out of 349 patients with abdominal hydatid disease. In 16 patients the spleen was the only organ involved, while in 3 patients the liver was also affected.

RESULTS

Eleven patients had splenectomy and in the other 8 the spleen was preserved: enucleation (n = 4), partial cystectomy and omentoplasty (n = 2) and cystojejunal Roux-en-Y anastomosis (n = 2). One (6%) patient died in the early postoperative period and 5 (29%) patients had postoperative complications. There was no significant difference between the splenectomy and spleen-preserving groups concerning median hospital stay and postoperative complication rate. The median follow-up in 15 patients was 52 (range 6-300) months. Two patients (13%) developed recurrence of the disease requiring re-operation at 2 and 3 years, respectively. Recurrence occurred in 1 (12%) patient in the splenectomy group and in 1 (14%) out of 7 patients in the spleen-preserving group.

CONCLUSION

In the present series it was possible to preserve the spleen in 8 (42%) of 19 patients, without significant increase of recurrent echinococcosis.

Tropisetron vs ondansetron for prevention of postoperative nausea and vomiting after laparoscopic cholecystectomy: a randomized double-blind, placebo-controlled study

BACKGROUND

Postoperative nausea and vomiting are observed in increased frequency after laparoscopic surgery. This study was performed in order to compare the efficacy of two 5-hydroxytryptamine-3 (5-HT3) receptor antagonists, ondansetron and tropisetron, in preventing postoperative nausea and vomiting (PONV) after laparoscopic cholecystectomy.

METHODS

Using a randomized, double-blind study design, 87 ASA I and II patients scheduled for laparoscopic cholecystectomy were randomly assigned to receive 4 mg ondansetron (Group A, n = 29), 5 mg tropisetron (Group B, n = 31), or placebo (Group C, n = 27) intravenously (IV) before induction of anesthesia. The end points evaluated were frequency of nausea, nausea intensity rated on a scale from 1 (mild) to 5 (most severe), frequency of vomiting, and need for rescue antiemetics. These parameters were measured immediately after surgery (0 h), at 3 h, 6 h, and 12 h postoperatively.

RESULTS

The frequency of nausea was significantly higher in group A (31.2%) compared to group B (14%) at 12 h postoperatively (p <0.01). However, patients of group A had significantly lower nausea scores at 3 h postoperatively compared to group B. Postoperative vomiting occurred in 13.8% of patients in group A and 9.6% of patients in group B throughout the whole study period (p = n.s.). The need for rescue antiemetics was similar between groups A and B. Both groups were superior to placebo concerning all studied parameters.

CONCLUSION

Our results show that ondansetron may be more effective in controlling nausea intensity during the first 3 h after laparoscopic cholecystectomy, while tropisetron has a longer-acting activity, with a major impact on nausea frequency at 12 h postoperatively.

[Unusual complications of the Peutz-Jeghers-syndrome in two consecutive generations of the same family]

The Peutz-Jeghers syndrome is an autosomal dominant inherited disease, characterized by the presence of hamartomatous polyposis of the gastrointestinal tract and perioral mucocutaneous pigmentation. The incidence of surgical complications in these patients is relatively rare, and correlates with the size and location of the polyps. We report on two complications of the Peutz-Jeghers syndrome which occurred in two generations of the same family. There was a perforation and an invagination of the small intestine. Both cases were treated by resection of the small intestine.

Continuous monitoring of arterial blood gases and pH during laparoscopic cholecystectomy using a Paratrend sensor

BACKGROUND

The safety of laparoscopic procedures has been studied broadly. The effects on cardiopulmonary function and reliable methods of monitoring concentrate more interest.

METHODS

A prospective study in 22 consecutive patients with ASA I and II was designed. The continuous assessment of alterations of arterial blood gases, pH, arterial pressure and heart rate during laparoscopic cholecystectomy by carbon dioxide pneumoperitoneum American technique was achieved using an intra-vascular multi-parameter sensor Paratrend.

RESULTS

Statistically significant increase of both PaCO2 and PE.CO2 in parallel and a corresponding decrease of pH were found in correlation with the duration of the pneumoperitoneum. The values of PaO2, Sat O2, base excess, H-CO3, mean arterial pressure and heart rate showed no statistically significant alterations at any time throughout the procedure. No differences were noted between younger patients and in the elderly or between patients with ASA I and II.

CONCLUSIONS

Intra-arterial blood-gas sensor ensures continuous on-line monitoring, but no abnormal and threatening changes occur during laparoscopic cholecystectomy in otherwise healthy people.

[Unusual complications of the Peutz-Jeghers-syndrome in two consecutive generations of the same family]

The Peutz-Jeghers syndrome is an autosomal dominant inherited disease, characterized by the presence of hamartomatous polyposis of the gastrointestinal tract and perioral mucocutaneous pigmentation. The incidence of surgical complications in these patients is relatively rare, and correlates with the size and location of the polyps. We report on two complications of the Peutz-Jeghers syndrome which occurred in two generations of the same family. There was a perforation and an invagination of the small intestine. Both cases were treated by resection of the small intestine.

Modern stapled Longo procedure vs. conventional Milligan-Morgan hemorrhoidectomy: a randomized controlled trial

BACKGROUND AND AIMS

Postoperative pain is the most distressing sequela of conventional hemorrhoidectomy. A modern alternative of circumferential mucosectomy has been proposed to reduce the pain in this procedure.

PATIENTS AND METHODS

This controlled trial included 80 patients with second to fourth degree hemorrhoidal disease operated on over a 2-year period. The patients were randomly allocated to undergo either the stapled Longo procedure (group 1) or Milligan-Morgan hemorrhoidectomy (group 2) under epidural anesthesia. The operating time, postoperative pain scores at 3, 6, 12, and 24 h, analgesic consumption, hospital stay, and complication rate were recorded. At follow-up the outcome and patient satisfaction were evaluated.

RESULTS

The mean operating time in group 1 was shorter than in group 2, postoperative pain scores at all time points and the mean epidural morphine requirement was lower, and mean hospital stay was shorter. The complication rate did not differ (three cases of postoperative bleeding in group 1 and two cases in group. At follow-up no recurrence or complains were recorded except three cases of mild incontinence (one in group 1 and two in group 2). The patients in group 1 (95%) were more satisfied than in group 2 (89%).

CONCLUSION

The Longo procedure is thus a simple, safe, and effective method that entails less postoperative pain, more satisfaction, and shorter hospital stay than the standard Milligan-Morgan hemorrhoidectomy.

Preincisional intravenous low-dose ketamine and local infiltration with ropivacaine reduces postoperative pain after laparoscopic cholecystectomy

BACKGROUND

The preincisional use of ketamine combined with local tissue infiltration with Ropivacaine may reduce noxious input during surgery. The goal of this study was to examine whether this combination improves postoperative pain control after laparoscopic cholecystectomy.

METHODS

A total of 55 patients were randomly assigned to one of three groups. Group 1 received placebos preincisional. Group 2 received preincisional saline IV and local infiltration with 20 ml ropivacaine (10 mg/ml). Group 3 received preincisional ketamine 1 mg/kg IV and local infiltration with 20 ml ropivacaine (10 mg/ml). Postoperative pain was rated at 0, 3, 6, 12, 24, and 48 h postoperatively by visual analogue scale scores (VAS). Cumulative analgesic consumption and time until first analgesic medication request were recorded.

RESULTS

Group 3 experienced significantly (p < 0.05) less pain than group 2 at 6 h and 12 h postoperatively. Groups 2 and 3 did not differ significantly by VAS at 0 h, 3 h, 24 h, and 48 h. Group 1 had significantly higher VAS scores than groups 2 and 3 at 0 h, 3 h, 6 h, 12 h, and 24 h postoperatively. The consumption of analgesics was significantly higher in group 1 than in groups 2 and 3. Although the consumption of analgesics was higher in group 3 than in group 2, this difference did not reach statistical significance. The time to first request for analgesics was significantly longer in groups 2 and 3 than in group 1, with no statistical difference between groups 2 and 3.

CONCLUSION

Preincisional treatment with low-dose IV ketamine and local infiltration with ropivacaine 1% reduces postoperative pain after laparoscopic cholecystectomy.

Deblurring of bilevel waveforms

An algorithm for processing closely spaced edges and accurately restoring their locations is presented. The convolution distortion model is based on interacting edges. The restoration algorithm takes three edges as input and forces the effects of two of them to cancel each other. Thus the third edge appears to be isolated and is located using a traditional edge detector. Experiments on bar code waveforms reveal that this approach outperforms the current commercial bar code readers.

On the recognition of printed characters of any font and size

We describe the current state of a system that recognizes printed text of various fonts and sizes for the Roman alphabet. The system combines several techniques in order to improve the overall recognition rate. Thinning and shape extraction are performed directly on a graph of the run-length encoding of a binary image. The resulting strokes and other shapes are mapped, using a shape-clustering approach, into binary features which are then fed into a statistical Bayesian classifier. Large-scale trials have shown better than 97 percent top choice correct performance on mixtures of six dissimilar fonts, and over 99 percent on most single fonts, over a range of point sizes. Certain remaining confusion classes are disambiguated through contour analysis, and characters suspected of being merged are broken and reclassified. Finally, layout and linguistic context are applied. The results are illustrated by sample pages.

Segmentation by texture using correlation

The correlation coefficients are used for segmentation according to texture. They are first evaluated on a set of square regions forming two levels of the quadratic picture tree (or pyramid). If the coefficients of a square and its four children in the tree are similar, then that region is considered to be of uniform texture. If not, it is replaced by its children. In this way, the split-and-merge algorithm is used to achieve a preliminary segmentation. It is followed by a grouping algorithm using the correlation coefficients and the region adjacency graph, plus a small region elimination step. The latter regions are grouped according to their gray level because texture cannot be defined reliably on very small regions. Examples of implementation on four pictures are included.

Global Shape Analysis by k-Syntactic Similarity

The k-syntactic similarity approach is couched in graphical representation terms and its ability to provide global recognition capability while retaining a low time complexity is explored. One potential application domain, that of composite shape decomposition into approximately convex subshapes, is described. This is shown to be equivalent to finding cycles within a particular graph. The approach yields valid decompositions in many cases of interest, and is capable of identifying those cases where additional semantic considerations are necessary for proper analysis. The permissible graph structures representing composite shapes given a reasonable set of relations are determined. Experimental results on nonideal data are given.

Algorithms for shape analysis of contours and waveforms

Algorithms for shape analysis are reviewed and classified under various criteria, whether they examine the boundary only or the whole area and whether they describe the original picture in terms of scalar measurements or through structural descriptions. The emphasis is on methodologies which have been popular during the last five years and among them, those which are information preserving.

The use of a syntactic shape analyzer for contour matching

Description of contours in terms of complex arcs allows the use of simple algorithms for matching. An example of such matchings for island contours is included.

A hierarchical syntactic shape analyzer

In many cases a picture is described in terms of various plane objects and their shape. This paper describes a parser whose input is a piecewise linear encoding of a contour and whose output is a string of high-level descriptions: arcs, corners, protrusions, intrusions, etc. Such a representation can be used not only for description but also for recognition. Previous syntactic techniques for contour description have often used high-level languages for the description of contours. This has been necessary in order to guarantee contour closure and eliminate the noise. In the present approach the numerical preprocessing of the contour removes most of the noise and also produces the answers to certain simple questions about its shape. Therefore, simpler grammars can be used for the contour description. Examples of descriptions of contours are given for handwritten numerals, white blood cells, and printed wiring circuit boards.