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Biomedical subjects

R M Walsh

Publications and source records attributed to R M Walsh.

At least 37 records · Page 2Linked to original sources
PubMed2001

Partial labyrinthectomy approach for brainstem vascular lesions.

Conventional wisdom has typically dictated that the bony labyrinth is an inviolate structure. This notion, however, was successfully challenged following the introduction of the partial labyrinthectomy approach, which was primarily used for the surgical management of cerebellopontine and petrous apex meningiomas. In this article, we discuss an extension of the technique of partial labyrinthectomy in a series of patients that has been used for the treatment of brainstem vascular lesions. We believe that this technique provides superior exposure to the brain stem when compared with conventional retrosigmoid and retrolabyrinthine approaches while reducing the inherent morbidity seen in transotic or petrosectomy approaches.

Adult↗
PubMed2001

The ascendance of laparoscopic splenectomy.

The application of laparoscopic techniques for abdominal procedures has been achieved with varying success. The general acceptance of laparoscopic splenectomy (LS) may be hindered by its infrequent performance and difficulty in manipulating the spleen. A retrospective review of splenectomies performed for primary splenic pathology was done to assess the role and outcome of LS. One hundred fifty LSs were performed from July 1995 through September 1999. Over that time period the proportion of LS performed increased steadily from 17 to 75 per cent of all splenectomies. The primary indications for splenectomy included immune thrombocytopenic purpura in 75 (50%), lymphoma/leukemia 36 (24%), and splenomegaly 19 (13%). There were 86 females and 64 males. Immediately before operation 36 patients (4%) had a platelet count <50,000/ mL, and 24 patients (16%) a hemoglobin <10 mg per cent. The mean operative time was 161 minutes with an average blood loss of 138 cm3 (<50-800). The mean morcellated weight of the entire group was 411 g (33-3300) indicating generally large splenic size. In the 37 patients with splenomegaly the mean weight was 735 g (293-3300). There were two conversions to open splenectomy. Two patients with hematologic malignancy, splenomegaly, and cytopenias died from overwhelming post-splenectomy sepsis (1.3%). Morbidity occurred in 14 (9%) with the most common complication being pancreatitis in seven (5%). The median length of postoperative stay was 2.4 days (range 1-5). In summary LS has rapidly replaced the open approach for nearly all elective splenectomies in adults and children. When performed with the patient in the lateral position it can be accomplished with minimal morbidity, even in complex patients, including those with splenomegaly.

Adolescent↗
PubMed2001

Laparoscopic splenectomy in patients with normal-sized spleens versus splenomegaly: does size matter?

Laparoscopic resection has become the standard means for removal of normal-sized spleens in many medical centers. The application of minimally invasive techniques in the setting of splenomegaly is less well defined and was previously considered a contraindication to the laparoscopic approach. The purpose of this prospective study of consecutive patients was to compare the outcomes of patients undergoing laparoscopic splenectomy for normal-sized spleens (150 g or less) versus those with clear evidence of splenomegaly (500 g or greater). One hundred forty-two patients met the inclusion criteria. The most common diagnosis in the normal-sized spleen group was idiopathic thrombocytopenia purpura (67 of 82, 82%). Malignant hematologic diseases (lymphoma and leukemia) were the most common diagnoses in the splenomegaly group (35 of 60, 58%). Mean operative times (127 vs 172 minutes) and estimated blood loss (123 vs 173 cm3) were lower for those patients with normal-sized spleens (P < 0.05). There were no statistical differences in conversion rates, lengths of stay, or complications between the two groups. We conclude that laparoscopic splenectomy is safe and effective in the setting of splenomegaly despite modest but statistically longer operative times and increased operative blood loss when compared with laparoscopic splenectomy for normal-sized spleens.

Adolescent↗
PubMed2001

Laparoendoscopic treatment of gastric stromal tumors.

Gastric stromal tumors are the most common submucosal mass found in the stomach. These tumors are most often diagnosed at endoscopy and can be accurately characterized by endoscopic ultrasound. They typically require surgical resection, and an increasing number of patients undergo laparoscopic resection. A combined laparoscopic/endoscopic, intragastric enucleation technique is described, and results are reported in 10 patients. Eleven nonmalignant lesions were excised, with a mean size of 4.12 (2.0 to 7.0) cm. There were no complications, and the median length of stay was 3.5 days. This surgical approach appears appropriate for predominantly intraluminal, benign-appearing lesions of the proximal stomach.

Adult↗
PubMed2000

Experience from a multidisciplinary "dizzy" clinic.

OBJECTIVE: To describe the experience of a combined otolaryngology and neurology multidisciplinary clinic in the evaluation, investigation, and management of patients with dizziness. STUDY DESIGN: Prospective clinical study. SETTING: Patients were seen in a tertiary referral, multidisciplinary clinic at The Toronto Hospital, University of Toronto, Ontario, Canada. INTERVENTION: A thorough history, formal otoneurologic examination, and appropriate laboratory investigations were performed. After their assessment, the patient's diagnoses were classified as peripheral, central, psychogenic, or undiagnosed and were then subdivided into specific clinical diagnoses. RESULTS: The first 812 consecutive patients seen in the multidisciplinary clinic from January 1, 1993 to December 31, 1998 are reported. Five hundred twenty-five (64.7%) patients were found to have a peripheral vestibular cause for their dizziness, 66 (8.1%) had a central cause, 108 (13.3%) had a diagnosis unknown, and 73 (9.0%) were thought to be psychogenic. In 40 (4.9%) patients, a peripheral and central cause were found. More than one type of peripheral disorder was noted in 17.9% of patients with a peripheral vestibular cause for their dizziness, and 12.3% of patients with a central cause for their dizziness had more than one specific type of central nervous system disorder. CONCLUSIONS: Most patients that were seen in a multidisciplinary clinic had a peripheral vestibular disorder. Central causes of dizziness were relatively uncommon. Serious diseases such as tumor, multiple sclerosis, and encephalitis were rare and unlikely to present with dizziness only. It is important to realize that a patient may have more than one type of disorder accounting for the symptoms, which may represent a spectrum of disease affecting the inner ear.

Adolescent↗
PubMed2000

The role of conservative management of vestibular schwannomas.

Although microsurgery is generally regarded as the conventional treatment of choice for most vestibular schwannomas, there remains a group of patients in whom a conservative management approach may be a desirable alternative. The aim of this study was to determine the natural history and outcome following the conservative management of 72 patients with unilateral vestibular schwannomas. The reasons for conservative management included poor general health, age, patient preference, small tumour size, minimal or no symptoms, and tumour in the only/better hearing ear. The mean duration of follow-up was 39.8 months (range 12-194 months). All patients underwent serial magnetic resonance imaging (MRI) for assessment of tumour growth. Patients were deemed to have failed conservative management if there was evidence of continuous or rapid radiological tumour growth and/or increasing symptoms or signs. The mean tumour growth rate, according to the 1995 guidelines of the American Academy of Otolaryngology/Head and Neck Surgery, was 1.16 mm/year (range: 0.75 9.65 mm/year). Approximately 83% of tumours grew at < 2 mm/year. Significant tumour growth was seen in 36.4%, no or insignificant growth in 50%, and negative growth in 13.6% of tumours. The growth rate of CPA tumours (1.4 mm/year) was significantly greater than that of IAC tumours (0.2 mm/year) (P = 0.001). Failure of conservative management, in which active treatment was required, occurred in 15.3%. The outcome of these patients appeared to be as favourable to a comparable group who underwent primary treatment, without a period of conservative management. The mean growth rate of tumours in patients who failed conservative management (4.2 mm/year) was significantly greater than that in patients who did not fail (0.5 mm/year) (P < 0.01). No factors predictive of tumour growth or failure of conservative management were identified. Deterioration of mean pure tone average (0.5, 1, 2, 3 kHz) and speech discrimination scores occurred regardless of whether radiological tumour growth was demonstrated or not. This study suggests that in a select number of cases of vestibular schwannoma, a conservative management approach may be appropriate. Regular follow-up with serial MRI is mandatory. Deterioration of auditory function occurs even in the absence of tumour growth.

Case-Control Studies↗
PubMed2000

Sensorineural hearing loss in ulcerative colitis.

Sensorineural hearing loss has been described in a small number of patients with ulcerative colitis. At present, it is not known whether this is a rare and sporadic association, or whether these reports represent an under recognised extra-intestinal manifestation of ulcerative colitis. The aim of this study was to determine the prevalence of hearing loss in patients with ulcerative colitis. Twenty patients with active ulcerative colitis (mean age 45 years) were recruited prospectively along with 20 healthy age- and sex-matched controls. Otoscopy, tympanometry and pure tone audiometry were performed. The activity of the disease was scored according to a 12-month cumulative disease activity index. No patients complained of auditory symptoms. Otoscopy and tympanometry were normal in all patients and controls. Pure tone audiometry showed significant sensorineural hearing loss over all frequencies in patients with ulcerative colitis compared with controls. This preliminary study indicates that subclinical sensorineural hearing loss is associated with ulcerative colitis. Further study is warranted to determine the nature of the relationship and its pathological basis.

Adult↗
PubMed2000

Consequences to hearing during the conservative management of vestibular schwannomas.

OBJECTIVE: To estimate the risk of loss of serviceable hearing during the conservative management of vestibular schwannomas. STUDY DESIGN: Retrospective case review. METHODS: Twenty-five patients with a radiological diagnosis of unilateral vestibular schwannoma were managed conservatively for a mean duration of 43.8 months (range, 12-194 mo). The pure-tone average (PTA) (0.5, 1, 2, and 3 kHz) and speech discrimination scores (SDS) were measured at regular intervals throughout the entire duration of follow-up. Serviceable hearing was defined using two criteria: 70% SDS/30 dB PTA (the 70/30 rule) and 50% SDS/50 dB PTA (the 50/50 rule). The size and growth rate of tumors were determined according to the American Academy of Otolaryngology-Head and Neck Surgery guidelines (1995). Intervention was recommended if there was evidence of continuous or rapid radiological tumor growth, and/or increasing symptoms or signs suggestive of tumor growth. RESULTS: The risk of loss of serviceable hearing for the total group was 43% using the 70/30 rule and 42% using the 50/50 rule. Tumor growth was considered significant (> 1 mm) in 8 tumors (32%) and nonsignificant in 17 (68%). The risk of loss of serviceable hearing for the tumor-growth group was 67% using the 70/30 rule and 80% using the 50/50 rule. In contrast, the risk of loss of serviceable hearing for the no tumor-growth group was 25% using the 70/30 rule and 14% using the 50/50 rule. No audiological factors predictive of tumor growth were identified. CONCLUSIONS: There is a significant risk of loss of serviceable hearing during the conservative management of vestibular schwannomas. This risk appears to be greater in tumors that demonstrate significant growth.

Adult↗
PubMed2000

The mini-laparoscopic intragastric resection of a gastroesophageal stromal tumor: a novel approach.

The laparoscopic wedge resection of gastric stromal tumors has been shown to be safe and effective. The removal of these tumors at the gastroesophageal junction is not amenable to a typical local resection because of anatomic inaccessibility and potential luminal restriction after resection. Also, an esophagogastrectomy is not tenable in the setting of benign disease. The recent advances in miniaturized laparoscopic instrumentation (2-mm diameter) have expanded the laparoscopic options, including intraluminal resection. The first intragastric mini-laparoscopic resection of the gastric stromal tumor at the gastroesophageal junction is reported.

Esophagogastric Junction↗
PubMed2000

The transmastoid partial labyrinthectomy approach to medial skull base lesions.

INTRODUCTION: It has long been thought that surgical disruption of the membranous labyrinth invariably results in sensorineural hearing loss and balance dysfunction. Recent evidence suggests that the inner ear can withstand such manipulation without loss of function. The technique of transmastoid partial labyrinthectomy has recently been described as a means of providing access to lesions of the medial skull base by removing part of the labyrinth and at the same time attempting to preserve hearing and vestibular function of the lateral semicircular canal (LSCC) and otolithic organs. PROCEDURE: An extended cortical mastoidectomy is performed and the posterior and middle cranial fossa dura are exposed widely. The posterior and superior semicircular canals are occluded at their ampullated ends and at the crus commune, and then resected. The LSCC and vestibule are left undisturbed. The petrous apex is removed and the medial end of the internal auditory canal is exposed. Posterior cranial fossa dural flaps are raised allowing access to the brainstem, petro-clival area and cerebellopontine angle. Temporal and suboccipital craniotomies can be performed, as required. RESULTS: Four patients underwent this procedure by a joint Otolaryngological-Neurosurgical team for access to the following lesions: three intra-axial pontine cavernomas and a basilar artery aneurysm. The preliminary hearing and balance results are discussed. CONCLUSIONS: The partial labyrinthectomy approach provides improved access to certain lesions of the medial skull base and requires less brain retraction compared with the retrolabyrinthine approach. It also has the potential to preserve serviceable hearing.

Adult↗
PubMed2000

The natural history of untreated vestibular schwannomas. Is there a role for conservative management?

OBJECTIVE: The aim of this study was to investigate the natural history and outcome following the conservative management of a group of patients with unilateral vestibular schwannomas. METHODS: 72 patients with a radiological diagnosis of unilateral vestibular schwannoma were managed conservatively because of poor general health, advanced age, patient preference, small tumour size, minimal symptoms, or tumour in the only/better hearing ear. All patients underwent serial magnetic resonance imaging for assessment of tumour growth, according to American Academy of Otolaryngology-Head & Neck Surgery guidelines (1995). The mean duration of follow-up was 37.8 months (range 12-194 months). Patients were deemed to have failed conservative management if there was evidence of continuous or rapid radiological tumour growth, and/or increasing symptoms or signs. RESULTS: The mean tumour growth rate was 1.16 mm/year (range -0.75 to 9.65 mm/year). Approximately 83% of tumours grew at less than 2 mm/year. Significant tumour growth (total growth > 1 mm) was seen in 36.4%, no or insignificant growth (0-1 mm) in 50%, and negative growth (< 0 mm) in 13.6% of tumours. The growth rate of cerebellopontine angle (CPA) tumours (1.4 mm/year) was significantly greater than that of tumours limited to the internal auditory canal (IAC) (0.2 mm/year) (p = 0.001). Failure of conservative management, in which active treatment was required, occurred in 15.3%. The outcome of these patients appeared to be as favourable as those who underwent primary treatment, without a period of conservative management. The growth rate of tumours in patients who failed conservative management (4.2 mm/year) was significantly greater than that in patients who did not fail (0.5 mm/year) (p < 0.01). No factors predictive of tumour growth were identified. Deterioration of mean pure tone average (0.5, 1, 2, 3 kHz) and speech discrimination scores occurred regardless of whether radiological tumour growth was demonstrated or not. CONCLUSIONS: The majority of vestibular schwannomas are slow growing, although, CPA tumours appear to grow faster than IAC tumours. Deterioration of auditory function occurs even in the absence of tumour growth. Although most Otolaryngologists and Neurosurgeons would agree that the treatment of choice for the majority of vestibular schwannomas is microsurgery, there remains a small group of patients in whom a conservative management approach may be a desirable alternative.

Adult↗
PubMed2000

Comparison of two radiologic methods for measuring the size and growth rate of extracanalicular vestibular schwannomas.

OBJECTIVE: To compare two methods for measuring the size and growth rate of extracanalicular vestibular schwannomas: the method recommended in 1995 by the American Academy of Otolaryngology--Head Neck Surgery (AAO-HNS) and the maximum cerebellopontine angle (CPA) tumor diameter, i.e., the method often used in radiologic reports. STUDY DESIGN: Retrospective clinical study. SETTING: Tertiary referral center. PATIENTS: Fifty-four patients with a radiologic diagnosis of unilateral extracanalicular vestibular schwannoma whose tumors were managed conservatively for a mean duration of 39.8 months (range 12-194 months). INTERVENTION: The extracanalicular component was measured by use of high-resolution magnetic resonance imaging (2- to 3-mm axial slices) at 6- to 12-month intervals. MAIN OUTCOME MEASURES: Tumor diameter was calculated by two methods. In the AAO-HNS method, the axial image with the largest extracanalicular tumor diameter was selected, and the maximum anteroposterior (A-P) and medial-lateral (M-L) tumor diameters were calculated. The A-P diameter was calculated parallel to the posterior surface of the petrous temporal bone, and the M-L diameter was calculated perpendicular to it. The size of the tumor was calculated as the square root of the product of these two diameters. In the maximum CPA method, the maximum CPA tumor diameter in any direction was also measured. RESULTS: There was no significant difference between the two methods for measuring the extracanalicular tumor size and growth rate, although the maximum CPA diameter method was consistently greater than the AAO-HNS method. There was a strong positive correlation between the two methods for assessing tumor size and growth. The A-P and M-L extracanalicular tumor diameters also showed a strong positive correlation, suggesting that the extracanalicular portion of vestibular schwannomas tends to enlarge equally in both these directions. CONCLUSION: There is a strong positive correlation between these two methods for assessing both the tumor size and the growth rate of extracanalicular vestibular schwannomas. However, because vestibular schwannomas tend to grow in both the A-P and the M-L directions, this suggests that the AAO-HNS method is preferable.

Adult↗
PubMed2000

Laparoscopic splenectomy for malignant diseases.

A variety of malignant diseases involving the spleen, both primary and metastatic, may require splenectomy for diagnosis or therapeutic reasons. The role of minimally invasive surgery in the management of malignant diseases involving the spleen is not well defined because of a lack of reported experience with laparoscopic splenectomy in this group. A reluctance to perform laparoscopic splenectomy in these patients may be explained by the technical and oncological challenges that often accompany malignant splenic diseases such as splenomegaly, perisplenitis, hilar lymphadenopathy, and fear of splenic disruption and tumor spillage. In our experience, the adoption of a lateral technique and the use of hand-assisted devices has allowed for the successful completion of laparoscopic splenectomy for malignant hematologic diseases including spleens up to 28 cm in length and greater than 3 kg morcellated weight. Laparoscopic splenectomy reliably alleviates the symptoms related to splenomegaly and reverses the hematologic abnormalities of hypersplenism. Although laparoscopic splenectomy for malignant diseases is feasible, the role of minimally invasive surgery in the staging of Hodgkin's lymphoma remains undetermined.

Hematologic Neoplasms↗
PubMed2000

Regeneration of the mammalian vestibular sensory epithelium following gentamicin-induced damage.

OBJECTIVES: The aims of this study are (1) to investigate if significant long-term recovery of mature hair bundle (MHB) numbers takes place following gentamicin-induced damage to the mammalian vestibular sensory epithelium and (2) to assess if the different MHB types in the vestibular sensory epithelium have a different susceptibility to ototoxic damage. METHODS: Gentamicin (8 mg in 0.1-mL sterile water) was injected transtympanically into one ear of guinea pigs, the contralateral ear acting as a control. The animals were killed at 4 days, 4 weeks, and 3 and 10 months post-treatment and the utricles (n = 38) were extracted from both ears. Mature hair bundle and immature-looking hair bundle (IHB) densities on the surface of the utricle were determined using scanning electron microscopy. RESULTS: The MHB density showed a significant decline between 4 days and 4 weeks post-treatment. There was greater loss of type I MHBs (tallest stereocilia comparable in height to the kinocilium) than type II MHBs (kinocilium taller than the tallest stereocilia). A significant increase in IHB density was seen at 4 weeks post-treatment, after which it declined rapidly. A significant but incomplete recovery in MHB density (to 66% of control value) was seen in the striolar region at 10 months post-treatment, and these were composed mainly of type II MHBs. CONCLUSIONS: It would appear that the mature mammalian vestibular sensory epithelium does have the capacity for long-term recovery of MHB numbers following gentamicin-induced damage, but this is limited and does not result in complete restoration of the epithelium. Type I MHBs are more susceptible to ototoxic damage than type II MHBs. Sommaire

Animals↗
PubMed1999

Laparoscopic splenectomy for non-Hodgkin lymphoma.

BACKGROUND AND OBJECTIVES: The spleen is frequently involved in patients with non-Hodgkin lymphoma (NHL). The indications for splenectomy in this disease include amelioration of symptoms from splenomegaly, correction of cytopenias, and the need to establish the diagnosis. The aim of this study was to determine the feasibility of laparoscopic splenectomy for patients with splenomegaly and NHL. METHODS: Retrospective review was made of patients who underwent laparoscopic splenectomy for suspected NHL. RESULTS: A total of 57 laparoscopic splenectomies have been performed in the lateral position; 9 of these patients had NHL. All patients had splenomegaly with a mean craniocaudal length of 17.8 cm and mean morcellated splenic weight of 765 gm. The mean operating-room time was 185 min, with a mean blood loss of 108 cc. None were converted to open splenectomy, and there was no mortality. The mean postoperative stay was 2-4 days. At a mean follow-up of 6.7 months, there have been no major complications or sepsis. CONCLUSIONS: Laparoscopic splenectomy is indicated in the setting of splenomegaly and suspected lymphoma. The operation is best performed in the lateral position, which is successful in patients with massive splenomegaly.

Humans↗
PubMed1999

Role of laparoscopy for Hodgkin's and non-Hodgkin's lymphoma.

An efficacious approach to the diagnosis and treatment of lymphoma requires the expertise of both physicians and surgeons. The surgeon frequently is required to provide an adequate tissue diagnosis, stage the disease, and treat complications of the disease such as splenomegaly. Often, abdominal and retroperitoneal operations are required which may be unnecessarily morbid. Minimally invasive surgical techniques may favorably impact on the work-up and treatment of lymphoma. Laparoscopy can expeditiously access retroperitoneal lymphadenopathy, sample abdominal lymph node groups, and perform splenectomy with low morbidity and rapid recovery. In Hodgkin's disease, laparoscopic staging with splenectomy may be the best modality for infradiaphragmatic staging to tailor initial treatment. Laparoscopic splenectomy is also effective in the treatment of the symptoms and hematologic derangements of splenomegaly or primary splenic lymphoma. The technique of laparoscopic splenectomy is emphasized.

Female↗
PubMed1999

Laparoscopic adrenalectomy for cancer.

We will review the literature on the operative techniques and patient outcomes of laparoscopic adrenalectomy for cancer. Further, in our own study, an analysis of the preoperative assessment, operative, and hospital course, and postoperative follow-up was performed on all patients undergoing a laparoscopic adrenalectomy for cancer or metastasis from October 1996 through February 1998. Twelve laparoscopic resections were performed in 11 patients. There were six males and five females with an average age of 62 years (range, 40 to 79). The mean American Society of Anesthesiologists (ASA) score was 3.1 (range, 2 to 4). All of the tumors except one were due to metastatic cancer. The metastatic sources included renal cell cancer (four), lung cancer (two), colon cancer (two), adrenal cancer (one), and melanoma (one). Seven patients required a left adrenalectomy, three underwent a right adrenalectomy, and one was bilateral. The approach was transperitoneal in eight cases and retroperitoneal in four. The mean size of the tumors was 5.9 cm (range, 1.8 to 12 cm). Operative time averaged 181 minutes (range, 100 to 315 minutes), and blood loss was 138 cc (range, 20 to 1,300 cc). Average hospital stay was 2.3 days (range, < 1 to 6 days). One patient required conversion to an open approach due to local invasion of the tumor into the lateral wall of the vena cava, which was resected with the specimen. This procedure resulted in the largest blood loss of the series (1,300 cc). All specimens had negative surgical margins. There was one complication (9%), a laceration of the epigastric artery, which was controlled laparoscopically. At a mean follow-up of 8.3 months (range, 0.5 to 19 months), there have been no port site or local recurrences. One patient has developed a new hepatic nodule, which is being worked up for metastatic disease. Ten of the 11 patients (91%) are currently alive; one has died of expansive cerebral metastases from melanoma.

Adrenal Gland Neoplasms↗