Anatomical and surgical aspects of splenic segmentectomies

Partial splenectomy in children undergoing liver transplantation or venous shunt for severe hypersplenism: A case control comparative study

BACKGROUND AND AIM

Hypersplenism is a consequence of portal hypertension and splenomegaly secondary to cirrhosis or portal cavernoma in children. In order to avoid persistent hypersplenism and splenomegaly after liver transplantation (LT) or venous shunt (VS), partial splenectomy (PS) may represent a relevant therapeutic option. The aim of this retrospective study was to evaluate the results of PS performed in children presenting hypersplenism.

METHODS

The following end-points were evaluated: (1) reversion of hypersplenism and its durability over time, (2) postoperative outcome, (3) courses of spleen size and volume and (4) comparison to a control group in which PS was not performed.

RESULTS

Between 1996 and 2020, 16 children underwent PS associated with LT (8 cases) for cirrhosis or VS (8 cases) for portal cavernoma. From Day 0 to 1 month, mean platelet and white blood cell counts (WBC) dramatically improved from 48 ± 19 at day 0 to 176 ± 70 × 10⁹/L (P < 0.0001) and from 2469 ± 853 to 7198 ± 3982/L (P = 0.001) respectively. PS allowed significant reduction of splenic length and volume from 176 ± 33 to 112 ± 24 cm (P < 0.0001) and from 1228 ± 464 to 450 ± 297 cm³ (P = 0.0003) respectively. After a mean follow-up of 92.6 ± 84.7 months (range: 4.1-210.7), 14 patients are alive with normal platelet and WBC counts and persistent spleen size reduction. Compared to control group, PS was associated with a significant platelet count rise from baseline to one year.

CONCLUSIONS

PS appears to be effective for treatment of hypersplenism and splenomegaly in combination with LT or VS without compromising outcome.

A systematic review of splenic artery variants based on cadaveric studies

PURPOSE

The splenic artery (SA) is the largest and most tortuous branch of the celiac trunk with a wide spectrum of variants, particularly in its terminal branches.

METHODS

The current study presents a systematic review of the English literature on the SA variations, with emphasis on its terminal branching patterns.

RESULTS

Thirty cadaveric studies (3132 specimens) were included in the analysis. The SA originated from the celiac trunk in 97.2%, from the abdominal aorta in 2.1% and from the superior mesenteric or the common hepatic artery in 0.7% of cases. A suprapancreatic course was observed in 77.4%, retropancreatic course in 17.8%, anteropancreatic course in 3.4% and intrapancreatic course in 1.3%. In the majority of cases, the SA bifurcated into superior and inferior lobar arteries (83.4%), with trifurcation and quadrifurcation in 11.3% and 2.7%, respectively. Five or more lobar branches (1.4%) and a single lobar artery (1.2%) were rarely identified. The distributed branching pattern was found in 72.7%, whereas the magistral pattern in 26.9%. The inferior and superior polar arteries (IPA and SPA) were found in 47.7% and 41.7% of cases, respectively, while polar artery agenesis was recorded in 28.2%. The SPA usually originated from the SA main trunk (53.6%) or from the superior lobar artery (33.1%). The IPA emanated mainly from the left gastroepiploic artery (53%), from the SA (23.5%) or the inferior lobar artery (21.9%). Intersegmental anastomoses between adjacent arterial segments were identified in 14.2%.

CONCLUSION

Knowledge of the SA aberrations is important for surgeons and radiologists involved in angiographic interventions.

Anatomy, immunohistochemistry, and numerical distribution of human splenic microvessels

The microvascular architecture of the spleen plays an important role in the immunological function of this organ. The different types of vessels are related to different reticular cells each with their own immunomodulatory functions. The present study describes an immunohistochemical and morphometric analysis of the various types of vessels in 21 human autopsy non-pathological splenic samples. On an area of 785,656.37 μm² for each sample, we classified and quantified the type and number of vascular structures, each according to their morphology and immunohistochemical profile, and obtained the ratios between them. The distribution of trabecular vessels and the characteristics of the venules are reviewed. In our material the so-called "cavernous perimarginal sinus" (anatomical structure previously described by Schmidt et al., 1988) was observed and interpreted as a curvilinear venule shaped by the follicle in contact with the trabecular vein. Our material comprised 261 trabeculae (containing 269 arterial sections and 508 venous sections), 30,621 CD34+ capillaries, 7739 CD271+ sheathed capillaries, 2588 CD169+ sheathed capillaries, and 31,124 CD8+ sinusoids. The total area (TA) (14,765,714.88 μm²) occupied by the sinusoidal sections of the 21 cases was much higher than the TA of the capillary sections (1,700,269.83 μm²). Similarly, the TA (651,985 μm²) occupied by the sections of the trabecular veins was much higher than the TA of the trabecular arteries (88,594 μm²). The total number of CD34+ capillaries and of sinusoids CD8+ was similar for the sum of the 21 cases, nevertheless there were large differences in each case. Statistically the hypothesis that the number of capillaries and sinusoids are present with the same frequency is discarded. In view of the absence of a numerical correlation between capillaries and sinusoids, we postulate that very possibly the arterial and the venous vascular trees are two anatomically independent structures separated by the splenic cords. We believe that this is the first work where splenic microvascularization is simultaneously approached from a morphometric and immunohistochemical point of view.

The use of porcine corrosion casts for teaching human anatomy

In teaching and learning human anatomy, anatomical autopsy and prosected specimens have always been indispensable. However, alternative methods must often be used to demonstrate particularly delicate structures. Corrosion casting of porcine organs with Biodur E20^® Plus is valuable for teaching and learning both gross anatomy and, uniquely, the micromorphology of cardiovascular, respiratory, digestive, and urogenital systems. Assessments of casts with a stereomicroscope and/or scanning electron microscope as well as highlighting cast structures using color coding help students to better understand how the structures that they have observed as two-dimensional images actually exist in three dimensions, and students found using the casts to be highly effective in their learning. Reconstructions of cast hollow structures from (micro-)computed tomography scans and videos facilitate detailed analyses of branching patterns and spatial arrangements in cast structures, aid in the understanding of clinically relevant structures and provide innovative visual aids. The casting protocol and teaching manual we offer can be adjusted to different technical capabilities and might also be found useful for veterinary or other biological science classes.

Laparoscopic partial splenectomy performed by monopolar saline-cooled radiofrequency coagulation

BACKGROUND

Partial splenectomy is preferred to total splenectomy when possible to reduce the risk of life-threatening infection. Several techniques have been described, each with its merits. Laparoscopic transection with monopolar saline-cooled radiofrequency coagulation has not been previously described.

PATIENTS AND METHODS

Two patients with enlarging cystic splenic lesions consented to laparoscopic partial splenectomy. In 1 case, high-power saline-cooled monopolar radiofrequency transection was performed with a laparoscopic sealing hook; the procedure was performed with a rigid resectoscope and ball diathermy in the other.

RESULTS

Both cases were performed without complications. Transection with the resectoscope and ball diathermy was combined with selective clamping of the splenic hilar vessels and was performed in 100 minutes with estimated blood loss of 250 mL. Transection with the sealing hook was performed in 80 minutes without hilar vessel clamping, with an estimated blood loss of 100 mL. No additional hemostatic agents were required for either case.

CONCLUSIONS

Laparoscopic partial splenectomy can be performed with monopolar saline-cooled radiofrequency for parenchymal transection and hemostasis in a simple and effective manner.

Horse spleen segmentation technique as large animal model of preclinical trials

The parenchymal distribution of the splenic artery was studied in order to obtain anatomical basis for partial splenectomy. Thirty two spleens were studied, 26 spleens of healthy horses weighing 320 to 450 kg, aged 3 to 12 years and 6 spleens of fetus removed from slaughterhouse. The spleens were submitted to arteriography and scintigraphy in order to have their vascular pattern examined and compared to the external aspect of the organ aiming establish anatomo-surgical segments. All radiographs were photographed with a digital camera and the digital images were submitted to a measuring system for comparative analysis of areas of dorsal and ventral anatomo-surgical segments. Anatomical investigations into the angioarchitecture of the equine spleen showed a paucivascular area, which coincides with a thinner external area, allowing the organ to be divided in two anatomo-surgical segments of approximately 50% of the organ each.

A new technique for spleen autotransplantation

PURPOSE

Although the efficacy of spleen autotransplantation is debated, this approach remains the only possibility for preserving splenic function after traumatic splenectomy. This report describes an alternative method for splenic autotransplantation in case of splenic trauma.

METHODS

After splenectomy, the organ was weighed and the undamaged part was cut transversely to prepare a segment of approximately 4 × 3 × 2 cm in size and of 35 g of weight to be transplanted. The greater omentum was pedunculated in its left lateral portion, and the previously prepared splenic tissue was implanted in a pouch created at the lower edge of the omentum. The omental peduncle containing the splenic tissue was fixed to the parietal peritoneum of posterior left upper quadrant of the abdomen where the native spleen was previously located.

RESULTS

This technique was performed in 4 patients after informed consent had been obtained. The functionality of the splenic implant was assessed after 3 months by abdominal computed tomography and scintigraphy. These exams showed the functioning of the trasplanted splenic tissue in all patients.

CONCLUSION

This new technique needs further evaluation, but it appears to be an easy and safe alternative for spleen autotransplantation.

Esplenectomia subtotal por via laparoscópica em cães

OBJETIVO: O objetivo deste trabalho foi determinar a exeqüibilidade, reprodutibilidade e segurança da esplenectomia subtotal por via laparoscópica e suas repercussões morfológicas, hematológicas, imunitárias e de depuração sangüínea, comparando esses dados com os obtidos na esplenectomia laparotómica. MÉTODO: Este estudo experimental foi conduzido de acordo com os princípios éticos de pesquisa experimental, propostos pelo Comitê de Ética em Experimentação Animal da UFMG. Quatorze cães adultos mestiços de ambos os sexos foram distribuídos em dois grupos (n = 7): Grupo 1 - Esplenectomia subtotal laparoscópica, preservando o polo superior suprido exclusivamente pelos vasos esplenogástricos; a secção esplênica e hemostasia foram realizadas utilizando um grampeador linear cortante laparoscópico com carga de 45 mm de extensão. Grupo 2 - Esplenectomia total, realizada por meio de laparotomia mediana. Depois de três meses, foram analisadas as alterações nos exames hematológico, imunitário e cintilográfico em todos os animais. Secções dos remanescentes esplênicos, fígado e linfonodos foram avaliadas histologicamente. RESULTADOS: Todos os procedimentos transcorreram sem complicações, não havendo morte operatória e com perda sangüínea mínima. Todos os animais sobreviveram à operação durante os três meses de acompanhamento. Após esse período, houve redução da contagem de plaquetas (p < 0,05) no Grupo 1. O restante dos exames hematológicos permaneceu normal. Os remanescentes esplênicos apresentaram arquitetura semelhante ao baço normal. Não houve alterações histológicas nos linfonodos e fragmentos hepáticos. CONCLUSÕES: É possível e segura a realização da esplenectomia subtotal por via laparoscópica no cão.

Late follow-up of patients submitted to subtotal splenectomy

BACKGROUND

Over the past 21years, we have performed more than 200 subtotal splenectomies, in which the upper splenic pole vascularized only by the gastrosplenic pole vascularized only by the gastrosplenic vessels is preserved, to treat different pathologic conditions. A meticulous follow-up of the postoperative results of this procedure is of fundamental importance.

METHODS

All patients undergoing subtotal splenectomy were invited to be reviewed. A total of 86 patients who had undergone surgery 1-20years ago were gathered; the surgical procedure was performed for one of the following conditions: portal hypertension due to schistosomiasis (n=43), trauma (n=31), Gaucher's disease (n=4), myeloid hepatosplenomegaly due to myelofibrosis (n=3), splenomegalic retarded growth and sexual development (n=2), severe pain due to splenic ischemia (n=2) and pancreatic cystadenoma (n=1). Patients underwent a hematological examination, an immunological assessment, abdominal ultrasonography, computed tomography, scintigraphy and endoscopy.

RESULTS

Increased white blood cell count and platelets were the only hematological abnormalities. No immunological deficit was found. Esophageal varices were still present in patients who underwent surgery because of portal hypertension although without rebleeding. The ultrasound, tomography and scintigraphy examinations confirmed the presence of functional splenic remnants without significant size alteration.

CONCLUSIONS

Subtotal splenectomy seems to be a safe procedure that can be useful in treating conditions involving the spleen. The functions of the splenic remnants are preserved during long periods of time.

Late postoperative follow-up of patients undergoing subtotal splenectomy

PURPOSE

Over the past 21 years, we have performed more than 200 subtotal splenectomies, in which the upper splenic pole vascularized only by the gastrosplenic pole vascularized only by the gastrosplenic vessels is preserved, to treat different pathologic conditions. A meticulous follow-up of the postoperative results of this procedure is of fundamental importance.

METHODS

All patients undergoing subtotal splenectomy were invited to be reviewed. A total of 86 patients who had undergone surgery 1 to 20 years ago were gathered; the surgical procedure was performed for one of the following conditions: portal hypertension due to schistosomiasis (n = 43), trauma (n = 31), Gaucher's disease (n = 4), myeloid hepatosplenomegaly due to myelofibrosis (n = 3), splenomegalic retarded growth and sexual development (n = 2), severe pain due to splenic ischemia (n = 2) and pancreatic cystadenoma (n = 1). Patients underwent a hematologic exam, an immunologic assessment, abdominal ultrasonography, computed tomography, scintigraphy and endoscopy.

RESULTS

Increased white blood cell count and platelets were the only hematological abnormalities. No immunologic deficit was found. Esophageal varices were still present in patients who underwent surgery because of portal hypertension although without rebleeding. The ultrasound, tomography and scintigraphy exams confirmed the presence of functional splenic remnants without significant size alteration.

CONCLUSIONS

Subtotal splenectomy seems to be a safe procedure that can be useful in treating conditions involving the spleen. The functions of the splenic remnants are preserved during long periods of time.

Antibody Response of Autogenous Splenic Tissue Implanted in the Abdominal Cavity of Mice

There is still controversy about the immunologic function of autotransplanted splenic tissue. In this study, splenic autotransplantation was performed in the abdominal cavity of mice, and the plaque-forming cell (PFC) assay was used to investigate the frequency of antibody-forming cells in response to sheep red blood cell (SRBC) immunization. BALB/c mice were divided into four groups according to the location of the autogenous graft: intraomental (IO), free peritoneal splenosis (FPS), retroperitoneal (RP), and nongrafted control (CT). Thirty days after surgery the mice were immunized intraperitoneally with SRBCs, and 4 days later splenic immunoglobulin M anti-SRBC-secreting cells were determined by counting the number of PFCs. All the immunized mice showed increased numbers of PFCs that were about 2 logs higher than those in the the nonimmunized controls (P < 0.005). The frequencies of anti-SRBC-producing cells in the tissues grafted in various sites of the abdominal cavity (IO, FPS, RP), in the normal spleen from nonoperated controls (CT), or in the sham-operated control group (SCT) were not notably different (5582 +/- 2475 PFC/10(7) cells for IO; 4849 +/- 1856 for FPS; 6604 +/- 2903 for RP; 5940 +/- 5029 for CT; and 6172 +/- 2203 for SCT). Similar histology with small architectural variations was observed in all implants; less white pulp was involved, and there was more congestion in the red pulp, with extensive sinusoids and reticular fiber proliferation. This study shows that the T cell-dependent antibody response in implanted splenic tissues is as efficient as in the intact spleen, with no difference between the graft sites studied. This immune response does not depend on the slight architectural variations observed in the splenic implants.

Near-total splenectomy: a new technique for the management of hereditary spherocytosis

OBJECTIVE

The authors used a new surgical technique of near-total splenectomy (NTS) and report their experience.

SUMMARY BACKGROUND DATA

Total splenectomy is indicated for the management of patients with hereditary spherocytosis but may be complicated by severe infections and thromboembolic events. Studies have shown that partial or subtotal parenchymal resections can lead to excessive regeneration of the residual parenchyma. The resulting onset of hemolysis requires total splenectomy in a significant portion of patients. Our hypothesis was that a more radical approach to open resection permanently decreases recurrent hemolysis while potentially ensuring immune function.

METHODS

This longitudinal cohort study included 42 patients with moderate to severe hereditary spherocytosis who underwent NTS according to an open procedure developed by the authors. The end criterion was to conserve a remnant spleen of 10 cm in size.

RESULTS

Patient age ranged between 2 and 42 years. Mean resected spleen weight was 580 g; mean remnant volume was 10 cm (range, 8-11 cm). A surgical complication (loss of spleen) occurred in 1 patient. Six-month to 6-year follow-up data was available on 22 patients; 21 of 22 showed preserved phagocytosis and normal blood circulation of the remnant; 1 of 22 experienced secondary remnant necrosis. On average, the remnant spleen grew back to four and a half times its postoperative size. No patients required transfusions, developed gallstones, or symptomatic hemolysis.

CONCLUSIONS

This new technique of NTS is safe, effective, and can minimize the late sequelae of secondary splenectomy.

Preservação do baço na pancreatectomia distal por trauma

OBJETIVOS: A esplenectomia simplifica a pancreatectomia distal no trauma mas tem o inconveniente de aumentar a vulnerabilidade do paciente às infecções. O objetivo é avaliar se a preservação do baço na referida cirurgia é exeqüível e segura. MÉTODOS: A preservação do baço foi feita em 52 pacientes (48%) entre 108 submetidos à pancreatectomia distal. Quarenta e cinco (86,5%) do sexo masculino e sete (13,5%) do sexo feminino. Idade variou de seis a 42 anos com média de 22,1 anos. Trauma penetrante foi a causa da lesão em 35 (67%) com 27 (77%) por arma de fogo e oito (23%) por arma branca. Contusão foi responsável pela lesão em 17 (33%). RESULTADOS: Não houve óbito. Fístula pancreática ocorreu em seis (11,5%) pacientes; coleção subfrênica em seis (11,5%); pancreatite em dois (3,8%); abcesso de parede em quatro (8%); pneumonia em quatro (8%). Quarenta pacientes tiveram lesões associadas. O ISS médio foi de 19,3. O baço apresentava lesão em 13 pacientes. Sete foram submetidos à esplenorrafia e seis à ressecção parcial. Em 51 pacientes o baço foi conservado com os vasos esplênicos. Em um caso foi feita a ligadura proximal e distal dos vasos esplênicos (técnica Warschaw). Permanência hospitalar média de 12 dias. CONCLUSÃO: A pacreatectomia distal com preservação do baço mostrou ser segura nos pacientes estáveis, mesmo na presença de lesões associadas. A ausência de óbitos e a participação de cirurgiões em fase de treinamento confirmam sua segurança.