Neuropilin-2 expression in breast cancer: correlation with lymph node metastasis, poor prognosis, and regulation of CXCR4 expression.

BACKGROUND: Neuropilin-2 (Nrp2) is a receptor for vascular endothelial growth factor-C (VEGF-C), which is a well-known lymphangiogenic factor and plays an important role in lymph node metastasis of various human cancers, including breast cancer. Recently, Nrp2 was shown to play a role in cancer by promoting tumor cell metastasis. CXC chemokine receptor 4 (CXCR4) also promotes tumor metastasis. In the previous studies, we demonstrated that VEGF-C and cytoplasmic CXCR4 expressions were correlated with poorer patient prognosis (BMC Cancer 2008,8:340; Breast Cancer Res Treat 2005, 91:125-132). METHODS: The relationship between Nrp2 expression and lymph node metastasis, VEGF-C expression, CXCR4 expression, and other established clinicopathological variables (these data were cited in our previous papers), including prognosis, was analyzed in human breast cancer. Effects of neutralizing anti-Nrp2 antibody on CXCR4 expression and chemotaxis were assessed in MDA-MB-231 breast cancer cells. RESULTS: Nrp2 expression was observed in 53.1% (60 of 113) of the invasive breast carcinomas. Nrp2 expression was significantly correlated with lymph node metastasis, VEGF-C expression, and cytoplasmic CXCR4 expression. Survival curves determined by the Kaplan-Meier method showed that Nrp2 expression was associated with reduced overall survival. In multivariate analysis, Nrp2 expression emerged as a significant independent predictor for overall survival. Neutralizing anti-Nrp2 antibody blocks cytoplasmic CXCR4 expression and CXCR4-induced migration in MDA-MB-231 cells. CONCLUSION: Nrp2 expression was correlated with lymph node metastasis, VEGF-C expression, and cytoplasmic CXCR4 expression. Nrp2 expression may serve as a significant prognostic factor for long-term survival in breast cancer. Our data also showed a role for Nrp2 in regulating cytoplasmic CXCR4 expression in vitro.

Totally laparoscopic sigmoid colectomy: a simple and safe technique for intracorporeal anastomosis.

BACKGROUND: Current techniques of laparoscopic colectomy require an abdominal incision for extraction of the specimen. Although this incision is smaller than that for open laparotomy incision, it may reduce the advantages of laparoscopic surgery. In totally laparoscopic sigmoid colectomy, intracorporeal anastomosis is technically difficult. A safe and simple technique for circularly stapled intracorporeal anastomosis is described. METHODS: After mobilization of the colon and division of the mesentery, a semicircumferential colotomy is made at the anterior colonic wall just proximal to the transection site. The anvil of a circular stapling device, secured with a Prolene suture, is introduced via the colotomy. The suture is advanced anteriorly so that the center rod of the circular stapling device penetrates the colonic wall. The colon is staple-transected at this point to secure the anvil on the proximal colon. A grasping forceps is brought through the rectum, and the specimen is extracted through the colotomy made at the distal staple line. After the colotomy is reclosed with a linear stapler, anastomosis is established using a hemidouble stapling technique. RESULTS: Totally laparoscopic sigmoid colectomies were performed for 16 patients with colon cancers. All the patients were treated laparoscopically without any complications. The average operation time was 180 min. Although one patient experienced wound infection, no major complications occurred. There was no mortality in this series. CONCLUSIONS: The procedure of totally intracorporeal anastomosis combined with transanal extraction of the specimen can be performed easily, enabling surgeons to achieve minimal invasiveness comparable with that of hybrid natural orifice translumenal endoscopic surgery (NOTES).

A simple and safe method for gastrojejunostomy in laparoscopic distal gastrectomy using the hemidouble-stapling technique: efficient purse-string stapling technique.

AIM: To describe a simple technique for intracorporeal circular-stapled gastrojejunostomy in laparoscopic distal gastrectomy with Roux-en-Y reconstruction. METHODS: After the stomach and duodenum were mobilized, gastrotomy was established in the anterior gastric wall. An anvil, which was secured with a suture needle, was inserted completely through the gastrotomy. The needle was advanced to the greater curvature of the gastric wall to enable penetration of the central rod into the gastric wall. Subsequently, the stomach was cut using a linear stapler to secure the anvil on the stomach and was sequentially transected using another linear stapler to achieve distal gastrectomy. Circular-stapled gastrojejunostomy was then performed intracorporeally using the hemidouble-stapling technique, while handling the shaft of the instrument via the umbilical incision. The jejunal stump was closed using a linear stapler. RESULTS: Gastrojejunostomies were successfully performed in 20 gastric cancer patients using this technique. None of the patients showed anastomotic leakage and/or stenosis. There were no mortalities in this series. CONCLUSIONS: Gastrojejunostomy performed using the above-mentioned technique was safe and simple. The most important feature of the technique was the elimination of the need for purse-string suture placement, as well as the achievement of better cosmesis using the transumbilical approach.

Totally laparoscopic low anterior resection for lower rectal cancer: combination of a new technique for intracorporeal anastomosis with prolapsing technique.

BACKGROUND: Laparoscopically assisted low anterior resection is difficult even for experienced surgeons because of difficulties in selecting the appropriate transection line and completing anastomosis in the narrow pelvic space. The prolapsing technique resolves these problems. We combined our new technique for intracorporeal anastomosis with this prolapsing technique and achieved a totally laparoscopic low anterior resection. METHODS: After the total mesorectal excision, a semi-circumferential colotomy is made at the anterior colonic wall just proximal to the proximal transection site. The anvil of a circular stapling device, secured with a Prolene suture, is introduced via the colotomy. The suture is advanced anteriorly so that the center rod of the anvil penetrates the colonic wall. The colon is staple-transected at this point to secure the anvil on the proximal colon. The distal rectum is everted and pulled transanally outside the body using a grasping forceps inserted from the anus. Staple-closure and transection of the distal rectum is performed under direct vision. Anastomosis is established using the double-stapling technique. RESULTS: Totally laparoscopic low anterior resections using this technique were performed for 7 patients with rectal cancer. There was no anastomotic leakage/stenosis. CONCLUSIONS: Our procedure can be performed easily, which enables surgeons to achieve minimal invasiveness compared with hybrid NOTES.

[An autopsied case of giant small cell carcinoma of the pancreas].

A 58-year-old man who complained of an abdominal tumor was admitted to our hospital. Abdominal CT scan showed that a 15-cm tumor occupied the entire right upper abdomen and that there were ascites and liver metastases. A liver biopsy was performed. The liver biopsy showed a small cell carcinoma pattern, but no definitive origin of the tumor was determined. Considering the extensive peritoneal invasion and multiple liver metastases, he received 2 / courses of cisplatin/etoposide chemotherapy, but his tumor became larger with concomitant abdominal pain and nausea. The patient suddenly died due to multiple organ failure caused by tumor necrosis. The autopsy revealed a pathological diagnosis of primary small cell carcinoma of the pancreas.

Spontaneous resolution of myopic foveoschisis and a macular hole with retinal detachment.

PURPOSE: The aim of this report was to describe a case of myopic foveoschisis and a macular hole with retinal detachment that resolved spontaneously. OBSERVATIONS: A 62-year-old woman with bilateral blurred vision was referred to our department. Her best-corrected visual acuity (BCVA) was 0.4 bilaterally; the standard equivalent refractive error was -17.0 diopters in the right eye and -18.75 diopters in the left eye. The axial length was 31.4 mm and 31.2 mm, respectively. After cataract surgery was performed, the BCVA of the right and left eye was 0.6 and 1.0, respectively. Four years later, slight macular traction, foveoschisis, and the macular hole had progressed in the left eye and the BCVA had decreased to 0.7. However, the macular hole had closed, the foveoschisis had resolved, and retinal detachment had mostly resolved three weeks later. The BCVA improved to 0.8. The macular hole did not reoccur and retinal detachment resolved completely after six more months. CONCLUSIONS AND IMPORTANCE: This case demonstrated that myopic foveoschisis and a macular hole with retinal detachment could improve spontaneously. It is necessary to decide carefully whether surgery is required or whether the patient should be observed.

Cytoplasmic CXCR4 expression in breast cancer: induction by nitric oxide and correlation with lymph node metastasis and poor prognosis.

BACKGROUND: Lymph nodes constitute the first site of metastasis for most malignancies, and the extent of lymph node involvement is a major criterion for evaluating patient prognosis. The CXC chemokine receptor 4 (CXCR4) has been shown to play an important role in lymph node metastasis. Nitric oxide (NO) may also contribute to induction of metastatic ability in human cancers. METHODS: CXCR4 expression was analyzed in primary human breast carcinoma with long-term follow-up. The relationship between nitrotyrosine levels (a biomarker for peroxynitrate formation from NO in vivo) and lymph node status, CXCR4 immunoreactivity, and other established clinico-pathological parameters, as well as prognosis, was analyzed. Nitrite/nitrate levels and CXCR4 expressions were assessed in MDA-MB-231 and SK-BR-3 breast cancer cell lines after induction and/or inhibition of NO synthesis. RESULTS: CXCR4 staining was predominantly cytoplasmic; this was observed in 50%(56/113) of the tumors. Cytoplasmic CXCR4 expression was significantly correlated with nitrotyrosine levels and lymph node metastasis. Kaplan-Meier survival curves showed that cytoplasmic CXCR4 expression was associated with reduced disease-free and overall survival. In multivariate analysis, cytoplasmic CXCR4 expression emerged as a significant independent predictor for overall and disease-free survival. Cytoplasmic expression of functional CXCR4 in MDA-MB-231 and SK-BR-3 cells was increased by treatment with the NO donor DETA NONOate. This increase was abolished by L-NAME, an inhibitor of NOS. CONCLUSION: Our data showed a role for NO in stimulating cytoplasmic CXCR4 expression in vitro. Formation of the biomarker nitrotyrosine was also correlated with CXCR4 expression and lymph node metastasis in vivo. In addition, cytoplasmic CXCR4 expression may serve as a significant prognostic factor for long-term survival in breast cancer.

Reduced incidence of intraoperative complications in a multicenter controlled clinical trial of triamcinolone in vitrectomy.

PURPOSE: To evaluate the benefits and potential complications of using triamcinolone acetonide (TA) in pars plana vitrectomy (PPV). DESIGN: Multicenter, prospective, controlled clinical trial. PARTICIPANTS: In total, 774 patients from 8 Japanese hospitals were enrolled, with 391 patients undergoing TA-assisted PPV and 383 control patients undergoing conventional PPV. INTERVENTION: Intraoperative use of TA to aid visualization of the vitreous. MAIN OUTCOME MEASURES: The incidence of intraoperative complications, including retinal breaks, was evaluated. Early postoperative complications, intraocular pressure (IOP), and adverse events occurring within 3 months of the operation were also monitored. RESULTS: The incidence of both retinal breaks and intraoperative retinal detachment was significantly lower in TA-assisted PPV than in conventional PPV. Retinal breaks were seen in 34 eyes (8.7%) undergoing TA-assisted PPV compared with 54 eyes (14.1%) undergoing conventional PPV (odds ratio [OR], 0.603; 95% confidence interval [CI], 0.381-0.955; P = 0.031). Retinal detachment was seen in only 3 eyes (0.8%) in which TA was used compared with 14 eyes (3.7%) in which TA was not used (OR, 0.204; 95% CI, 0.057-0.727; P = 0.014). In total, 388 eyes in the TA-assisted PPV group (99.2%) and 374 eyes in the conventional PPV group (97.6%) were followed up for 3 months after the operation. Although the mean postoperative IOPs were comparable in both groups, antiglaucoma eye drops were used more frequently by patients in the TA-assisted group than by those in the conventional PPV group (OR, 1.673; 95% CI, 1.126-2.484; P = 0.011). No serious adverse events, such as endophthalmitis or retinal degeneration, were observed in either group. CONCLUSIONS: Intraoperative use of TA reduced the incidence of retinal breaks and retinal detachments in eyes undergoing PPV. There were no serious adverse events related to the intraoperative use of TA. Although antiglaucoma eye drops were required more frequently after TA-assisted PPV than after conventional PPV, IOP was well-controlled in both groups.

Nitric oxide in breast cancer: induction of vascular endothelial growth factor-C and correlation with metastasis and poor prognosis.

PURPOSE: Metastasis to regional lymph nodes through the lymphatic vessels is a common step in the progression of cancer. Recent evidence suggests that tumor production of vascular endothelial growth factor-C (VEGF-C) promotes lymphagiogenesis, which in turn promotes lymphatic metastasis. Nitric oxide (NO) may also increase metastatic ability in human cancers. EXPERIMENTAL DESIGN: Nitrite/nitrate levels and VEGF-C production were assessed in MDA-MB-231 breast cancer cells after induction and/or inhibition of NO synthesis. Formation of nitrotyrosine, a biomarker for peroxynitrate formation from NO in vivo, was analyzed in primary human breast carcinoma with long-term follow-up. The relationship between nitrotyrosine levels and lymph node status, VEGF-C immunoreactivity, and other established clinicopathologic variables, as well as prognosis, was analyzed. RESULTS: Production of nitrite/nitrate and VEGF-C in MDA-MB-231 cells was increased by treatment with the NO donor DETA NONOate. The NO synthase inhibitor N(G)-nitro-l-arginine methyl ester eliminated this increase. High-grade nitrotyrosine staining was observed in 57.5% (65 of 113) of the invasive breast carcinomas. Nitrotyrosine levels were significantly correlated with VEGF-C immunoreactivity and lymph node metastasis. Survival curves determined by the Kaplan-Meier method showed that high nitrotyrosine levels were associated with reduced disease-free and overall survival. In multivariate analysis, high nitrotyrosine levels emerged as a significant independent predictor for overall survival. CONCLUSIONS: Our data showed a role for NO in stimulating VEGF-C expression in vitro. Formation of its biomarker nitrotyrosine was also correlated with VEGF-C expression and lymph node metastasis. Furthermore, high nitrotyrosine levels may serve as a significant prognostic factor for long-term survival in breast cancer.

[Liposarcoma of the spermatic cord associated with rectum cancer: a case report].

We report a case of liposarcoma of the spermatic cord associated with rectum cancer. A 78-year-old man visited our hospital with a complaint of painless left inguinal mass. He also showed constipation and bloody bowel discharge, rectum cancer was diagnosed by further evaluation. Ultrasonography, computed tomography and magnetic resonance imaging revealed a 2 x 4 x 6 cm mass in the left spermatic cord. Left high orchiectomy for the left inguinal tumor and Hartmann's procedure for rectum cancer was performed. Histologically, the mass in the left spermatic cord was well differentiated liposarcoma and rectum cancer was poorly differentiated adenocarcinoma. He died from rectum cancer with no evidence of recurrence of liposarcoma of the left spermatic cord after follow up for 6 months.

[A case of stage IV advanced gastric cancer responding to TS-1/CDDP neoadjuvant chemotherapy which leads to a pathological complete response].

A 72-year-old male with advanced gastric cancer (cT3N2M0H0P0CY1, cStage IV) was treated with TS-1/CDDP as neoadjuvant chemotherapy. TS-1 (60 mg/m(2)/day) was orally administered for 3 weeks followed by 2 drug free weeks as a course, and CDDP (60 mg/m(2)) was administered by intravenous drip on day 8. After the fourth course,a significant tumor reduction was obtained. Total gastrectomy, splenectomy, and D 2 type nodal dissection were performed. The histological diagnosis revealed complete disappearance of cancer cells in the stomach and all of the lymph nodes, which is a so-called pathological complete response. The patient has now been in good health without a recurrence for 24 months after surgery. This case suggests that neoadjuvant chemotherapy with TS-1/CDDP is a potential regimen for advanced gastric cancer.

[A case of advanced gastric cancer with peritoneal dissemination responding to S-1/CDDP neoadjuvant chemotherapy].

The patient was a 72-year-old male diagnosed with type III poorly-differentiated adenocarcinoma in the lesser curvature by gastric fiberscopy. An abdominal computed tomography (CT) scan showed the thickness of the gastric wall and the enlarged lymph node around the stomach and laparoscopic examination revealed peritoneal dissemination. The patient received neoadjuvant combined chemotherapy with S-1 and CDDP. S-1 (100 mg/day) was orally administered for 3 weeks followed by 2 drug-free weeks as a course, and CDDP (100 mg/body) was administered by intravenous drip on day 8. After the third course, significant tumor reduction was obtained. Total gastrectomy, splenectomy and D2 nodal dissection were performed. Peritoneal dissemination disappeared, and the histological diagnosis revealed complete disappearance of cancer cells in the ascites and no metastasis in all lymph nodes. The patient has now been in good health with no recurrence for 22 months after surgery. The combined neoadjuvant chemotherapy with S-1 and CDDP can be an effective treatment of choice for advanced gastric carcinoma with peritoneal dissemination.

Pattern-reversal visual evoked potentials in patients with human T-lymphotropic virus type 1 uveitis.

PURPOSE: The purpose of this study was to evaluate the possible injury in the optic pathway by measuring P100 peak latency of pattern-reversal visual evoked potentials (PVEPs) in patients with human T-lymphotropic virus type 1 uveitis (HU). METHODS: The P100 peak latency of PVEP was measured during the period without macular abnormalities observed by fluorescein angiography in 23 patients (46 eyes) with HU and 24 patients (48 eyes) with Vogt-Koyanagi-Harada disease (VKH) with a corrected visual acuity of 20/25 or more. To determine the normal upper limit of P100 peak latency, PVEPs were measured in 31 normal subjects (31 eyes). In addition, in the HU patients, the serum anti-HTLV-1 antibody titer was measured by particle agglutination assay within 3 months of PVEP recording, and the period of HU was retrospectively surveyed. RESULTS: Delayed latency was observed in 4 (7 eyes) of the 23 patients (46 eyes) with HU but none of the 24 patients (48 eyes) with VKH. All four patients with delayed latency showed a serum anti-HTLV-1 antibody titer of more than x4000. The HU period in the HU patients was 0.2-14.0 years, and the HU periods in the four patients with delayed latency were 0.8, 2.7, 4.2, and 14.0 years, respectively. CONCLUSIONS: We measured pattern-reversal visual evoked potentials and observed delayed P100 peak latency in 7 of the 46 eyes in 4 (17.4%) of the 23 HU patients. This suggests injury in the optic pathway including the optic nerve by HTLV-1 in some patients with HU. In the future, consideration should also be given to the possible development of optic neuropathy due to HTLV-1.

[Case report of advanced breast cancer responding to capecitabine and trastuzumab combination therapy].

We conducted a concomitant administration of capecitabine (2,400 mg/day for 21 days followed by a 7-day interval) and trastuzumab (2 mg/kg weekly) to a 73-year-old female patient with impaired lower limb function diagnosed with bilateral breast cancer. The patient had a complete response (CR) to pulmonary metastases, and carcinoembryonic antigen (CEA) level had normalized from 46.4 ng/ml to 0.6 ng/ml. Left mastectomy was performed in order to control bleeding from tumors. No adverse events attributable to medication were observed. The concomitant administration of capecitabine and trastuzumab is a promising therapy with the potential to greatly improve patient quality of life (QOL).

[Combined chemotherapy with weekly Paclitaxel and doxifluridine for advanced and recurrent gastric cancers].

We conducted combined therapy of weekly paclitaxel and doxifluridine (5'-DFUR) for 23 cases of advanced and recurrent gastric carcinomas to investigate their efficacy and safety. Subjects included 7 unresectable cases, 5 noncurative resection cases, and 11 recurrent cases. Twenty of the 23 subjects had a history of prior treatment with another anticancer drug. The treatment regime consisted of one course comprising 70 mg/m(2)of paclitaxel weekly for three consecutive weeks followed by one week rest, combined with 800 mg/day of 5'-DFUR orally. Results revealed a response rate of 17.6% (3/17), with 2 cases of CR, 1 case of PR, 10 cases of NC, and 4 cases of PD. One of the CR cases was an unresectable case involving a primary tumor, liver metastasis, and abdominal lymph node metastasis, while the other was a recurrent case involving abdominal lymph node metastasis. The median survival period was 387 days. The one-and two-year survival rates were 52% and 24%, respectively. In terms of adverse effects, there were only single cases of grade 3 leukopenia and grade 3 neutropenia, with no cases of grade 4 hemotoxicity. Both patients could be treated as outpatients. Combination therapy of weekly paclitaxel and 5'-DFUR can be an effective and safe therapy for advanced and recurrent gastric carcinomas.

Prognostic significance of vascular endothelial growth factor D in breast carcinoma with long-term follow-up.

PURPOSE: Expression of angiogenic and lymphangiogenic factors by tumors may influence the route of metastatic spread. The angiogenic factor vascular endothelial growth D (VEGF-D) is implicated in the development of lymphatic vessels and promotion of lymphatic metastases. The purpose of this study is to determine whether VEGF-D correlates with lymph node metastasis or prognosis. EXPERIMENTAL DESIGN: We assessed VEGF-D expression using immunohistochemistry in 105 invasive breast carcinomas with long-term follow-up. The relationship among VEGF-D expression, lymph node status, and other established clinicopathological parameters was assessed. Whether VEGF-D expression plays prognostic role in breast cancer was also investigated. RESULTS: VEGF-D expression was identified in 86 cases (81.9%). Positive VEGF-D was significantly correlated with lymph node metastasis (P = 0.0238) and high c-erbB-2 expression (P = 0.0211). Survival curves determined by the Kaplan-Meier method and univariate analysis demonstrated that positive VEGF-D was associated with both disease-free survival (P = 0.0023) and overall survival (P = 0.0222). In multivariate analysis using the Cox regression model, positive emerged as an independent indicator for disease-free survival (P = 0.0452). CONCLUSIONS: VEGF-D expression is associated with lymph node metastasis and may be a novel prognostic factor in breast cancer. VEGF-D may be useful in the treatment of breast cancer as a decision-making biomarker for aggressive treatment after operation.

Flt-4-positive vessel density correlates with vascular endothelial growth factor-d expression, nodal status, and prognosis in breast cancer.

PURPOSE: Metastasis to the regional lymph nodes through the lymphatic vessels is a common step in the progression of cancer and an important prognostic factor in many types of cancer. Recent evidence suggests that tumor lymphangiogenesis promotes lymphatic metastasis, and that the presence of Flt-4 on tumor blood and lymphatic vessels may play a important role in mediating lymphangiogenic factor-induced neovascularization. We assessed flt-4-positive vessel density (FVD) in breast cancer, and examined whether FVD associates with lymph node metastasis, VEGF-D expression, or prognosis. EXPERIMENTAL DESIGN: One hundred three invasive breast carcinomas with long-term follow-up were included in our study. Flt-4 was assessed using immunohistochemistry, then we analyzed the relationship between FVD and lymph node status, as well as VEGF-D expression and other established clinicopathological parameters. The relationship between FVD and prognosis was also investigated. RESULTS: Mean FVD of "hot spot" was 29.3 +/- 22.5 for each case. FVD was correlated significantly with lymph node metastasis (P < 0.0001), VEGF-D expression (P = 0.0019), tumor size (P = 0.0015), estrogen receptor (P = 0.0211), progesterone receptor (P = 0.0462), and c-erbB-2 (P = 0.0326). Survival curves determined by the Kaplan-Meier method and univariate analysis demonstrated that high FVD was associated with both worse disease-free survival (P = 0.0035) and overall survival (P = 0.0336). CONCLUSIONS: Increased FVD was correlated with lymph node metastasis and VEGF-D expression. High FVD may be a significant unfavorable prognostic factor for long-term survival in breast cancer. It is possible that Flt-4 becomes a target for antiangiogenic therapy to breast cancer.

Metastatic somatostatinoma of the chest wall.

A 72-year-old male was diagnosed as having a thoracic tumor in the left chest wall five years after resection of primary pancreatic somatostatinoma. The tumor was suggestive of metastasis to the chest wall or to the left lung from the previously resected somatostatinoma based on the abnormally elevated serum somatostatin level. Percutaneous biopsy confirmed that the lesion was an islet cell tumor and thoracotomy demonstrated metastasis to the left third rib without involvement of the left lung. Our case represents a rare documentation of somatostatinoma metastatic to the chest wall for which complete resection was performed.

Incidence of acute endophthalmitis after triamcinolone-assisted pars plana vitrectomy.

PURPOSE: To report the incidence of acute endophthalmitis after triamcinolone acetonide-assisted pars plana vitrectomy (PPV). DESIGN: A retrospective multicenter interventional case series collected over 23 months. METHODS: We retrospectively reviewed the charts of all patients who underwent triamcinolone-assisted PPV at seven academic clinical centers or eye hospitals from January 2002 to November 2003. RESULTS: Of a total of 1,886 cases, only 1 case showed acute endophthalmitis due to Staphylococcus epidermidis (0.053%). No other cases showed any signs of postoperative endophthalmitis. CONCLUSION: Intraoperative use of triamcinolone during PPV is not a high risk factor for acute endophthalmitis.

Residual bed thickness and corneal forward shift after laser in situ keratomileusis.

PURPOSE: To prospectively assess the forward shift of the cornea after laser in situ keratomileusis (LASIK) in relation to the residual corneal bed thickness. SETTING: Miyata Eye Hospital, Miyazaki, Japan. METHODS: Laser in situ keratomileusis was performed in 164 eyes of 85 patients with a mean myopic refractive error of -5.6 diopters (D) +/- 2.8 (SD) (range -1.25 to -14.5 D). Corneal topography of the posterior corneal surface was obtained using a scanning-slit topography system before and 1 month after surgery. Similar measurements were performed in 20 eyes of 10 normal subjects at an interval of 1 month. The amount of anteroposterior movement of the posterior corneal surface was determined. Multiple regression analysis was used to assess the factors that affected the forward shift of the corneal back surface. RESULTS: The mean residual corneal bed thickness after laser ablation was 388.0 +/- 35.9 microm (range 308 to 489 microm). After surgery, the posterior corneal surface showed a mean forward shift of 46.4 +/- 27.9 microm, which was significantly larger than the absolute difference of 2 measurements obtained in normal subjects, 2.6 +/- 5.7 microm (P<.0001, Student t test). Variables relevant to the forward shift of the corneal posterior surface were, in order of magnitude of influence, the amount of laser ablation (partial regression coefficient B = 0.736, P<.0001) and the preoperative corneal thickness (B = -0.198, P<.0001). The residual corneal bed thickness was not relevant to the forward shift of the cornea. CONCLUSIONS: Even if a residual corneal bed of 300 microm or thicker is preserved, anterior bulging of the cornea after LASIK can occur. Eyes with thin corneas and high myopia requiring greater laser ablation are more predisposed to an anterior shift of the cornea.