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Variations in Hook of Hamate Morphology: A Cadaveric Analysis
Abstract
Purpose:
The hook of the hamate is an anatomical structure that separates the ulnar border of the carpal tunnel from Guyon's canal and serves as a landmark for surgeons. The hook of the hamate is also subject to fracture from injury. We hypothesize that there are variations in the hook of the hamate in the general population.
Methods:
One thousand pairs of hamates (2,000 hamates) from the Hamann-Todd Collection at the Cleveland Natural History Museum were analyzed. The height of the hook of the hamate and the total height of the hamate bone were measured using digital calipers. The hook height ratio was defined as the hook height divided by the total height of the hamate. Statistical analysis was performed using unpaired Student's t test to determine differences in sex and race.
Results:
The mean hook height was 9.8 ± 1.4 mm (range, 2.5-15.9 mm), whereas the mean hook height ratio was 0.42 ± 0.04 (range, 0.15-0.56). There was a 3.1% (62/2,000) incidence of abnormally small hooks, which we classified as hypoplastic and aplastic. Of the hypoplastic hooks, 55% (24/44) were bilateral, whereas 44% (8/18) of the aplastic hooks were bilateral. The incidence of variation in size in the hook of the hamate was highest in white females (9.3%) and lowest in black males (1.4%).
Conclusions:
Abnormalities in hook of hamate anatomy are common in the general population, especially in white females.
Clinical relevance:
Knowledge of anatomic variation in the hook of the hamate may provide additional insight into surgeons' palpation of bony anatomy, interpretation of imaging studies, and use of the hook as a landmark during surgery.
... Subtypes related to hamate morphology have been shown in the literature. [6,18,19] However, no study has been conducted on the effect of hamate morphology on wrist traumatic situations. In our study, we observed that the morphological types of the hamate bone had no effect on the distal radius fracture pattern. ...
Background: In this study, we examined whether carpal bones (lunate, hamate, capitate) morphologies and fourth metecarp-capitate articulation have an effect on the distal radius fracture pattern.
Methods: 206 patients who applied to the emergency department with distal radius fracture between 2016-2020 were included in the study. Preoperative and pre-reduction x-ray films of the patients were examined. Lunate, hamate, capitate morphologies and 4.metacarp articulation analyzed and classified. Distal radius fracture types were classified according to AO and Fernandez. The relationship between carpal bone morphology and distal radius fracture type was analyzed.
Results: This study consisted of 101 men and 103 women. AO fracture types and carpal bone morphologies (lunate joint type according to Viegas, lunate type according to Zapico, capitate morphology, hamate morphology and capitate-4 metacarpal joint morphology) did not differ significantly (p > 0.05). Fernandez fracture types and carpal bone morphologies (lunate joint type according to Viegas, lunate type according to Zapico, capitate morphology, hamatum morphology and capitate-4.metacarp joint morphology) were compared, there was no significant difference (p > 0.05).
Conclusion: As a result, no clear relationship could be demonstrated between carpal bone morphology and distal radius fracture pattern.
... 18 In an anatomical study of 2000 hamate bones, the HH was found abnormally small in 62 cases (3.1%). 19 The percentage was higher in Caucasian females (9.3%). Aplasia was defined by a height of the HH less than 4 mm (0.9% cases). ...
The hook of hamate is a complex anatomical region with many small but important structures. A sound knowledge of anatomy along with a systematic ultrasound technique can help delineate a variety of disorders. In this pictorial review, we discuss the ultrasound anatomy and the possible pathologies that can be encountered in this region.
Background:
Abundant literature exists on the morphology of the carpal tunnel. Despite this, the shape of the carpal tunnel has been reported erratically, and most studies did not attempt to correlate findings with measurements taken from cadavers. The objective of this study was to perform a morphological analysis, determine the shape and mean dimensions of the carpal tunnel, determine the level of the narrowest area of the tunnel, and establish a set of values capable of serving as a reference for carpal tunnel release.
Methods:
The carpal tunnels of 20 fresh cadaveric hands were dissected, and acrylic casts were created and measured using industrial computed tomography.
Results:
Of the 20 casts, 19 were shaped like elliptic cylinders, with little variation in their measurements along the length. The location of the narrowest section of the carpal tunnel is very different among casts, and the length of the roof of the carpal tunnel ranged from 21.26 to 29.86 mm.
Conclusions:
The most common shape of the carpal tunnel is an elliptic cylinder. Because of the unpredictability of the location of the narrowest area of the carpal tunnel, carpal tunnel release must continue through all extension of its roof. We advise that the release should rarely be extended distally more than 30 mm from the distal palmar wrist crease, which corresponds, in most cases, to the middle of the pisiform.
Fractures of the hamate hook are common among professional athletes. The recommended treatment for this is hamate hook excision. The purpose of this study is to evaluate the hand grip strength after hamate hook resection at different levels. Six cadaver forearm flexor digitorum profundus tendons were loaded with 5- to 15-kilograms force and grip strength was subsequently measured. The same measurements were performed in five hamate hook conditions: normal, one-third, two-thirds, total hamate excision, and after perihamate ligament reconstruction. Multilevel mixed-effect models were used to calculate the scaling ratios after each surgical intervention and compared them to a normal hamate hook. We found a 25%, 36%, 47% reduction, and 7% increase (107% of baseline) in grip strength after one-third, two-thirds, total bone was resected, and after perihamate ligament reconstruction, respectively. Our study shows an association between grip strength reduction and the level of hamate hook resection. Perihamate ligament reconstruction is recommended as it restores grip strength to normal.
The assessment of bone mainly relies on standard radiographs, CT, MRI, and bone scintigraphy depending on the anatomic region complexity and clinical scenario. Ultrasound (US), due to different acoustic impedance between soft tissues and the bone cortex, only allows the evaluation of the bone surfaces. Nevertheless, US can be useful in the evaluation of several bone disorders affecting the limbs as a result of its tomographic capabilities and high definition. This pictorial review article summarises our clinical experience in adults and reviews the literature on US bone examination. We first present the US appearance of normal bone and the main congenital anatomic variations, after which we illustrate the US findings of a variety of bone disorders. Although US has limits in bone assessment, its analysis must be a part of every musculoskeletal US examination.
OBJECTIVE: To examine the relation between selected nonoccupational risk factors and surgery for carpal tunnel syndrome.
DESIGN: Case-control study using an administrative database.
PARTICIPANTS: Enrollees of New Jersey Medicine or Medicaid programs during 1989 to 1991.
MEASUREMENTS: The outcome of interest was open or endoscopic carpal tunnel release. We examined the relation between carpal tunnel release and diabetes mellitus, thyroid disease, inflammatory arthritis, hemodialysis, pregnancy, use of corticosteroids, and hormone replacement therapy.
MAIN RESULTS: In multivariate models, inflammatory arthritis was strongly associated with carpal tunnel release (odds ratio [OR] 2.9; 95% confidence interval [CI] 2.2, 3.8). However, corticosteroid use also appeared to be associated with a greater likelihood of undergoing carpal tunnel release, even in the absence of inflammatory arthritis (OR 1.6; 95% CI 1.2, 2.1). Diabetes had a weak but significant association with carpal tunnel release (OR 1.4; 95% CI 1.2, 1.8), as did hypothyroidism (OR 1.7; 95% CI 1.1, 2.8), although patients with hyperthyroidism did not have any change in risk. Women who underwent carpal tunnel release were almost twice as likely to be users of estrogen replacement therapy as controls (OR 1.8; 95% CI 1.0, 3.2).
CONCLUSIONS: Although inflammatory arthritis is the most important nonoccupational risk factor for carpal tunnel release, these data substantiate the increase in risk associated with diabetes and untreated hypothyroidism. Further investigation in detailed clinical studies will be necessary to confirm whether changes in corticosteroid use and hormone replacement therapy offer additional means of risk reduction for this common condition.
With use of a comprehensive medical records-linkage system, we identified the comorbid conditions and risk factors in the residents of Rochester, Minnesota, who had a diagnosis of carpal tunnel syndrome during 1961 through 1980. In 43.2% of the 1,016 patients, no associated conditions were found on review of the medical records, whereas associated conditions were documented in 56.8%. The most frequent of these conditions were Colles' fracture, rheumatoid arthritis, hormonal agents or oophorectomy (or both), diabetes mellitus, and, among men, occupations that involved excessive use of the hands. Rheumatoid arthritis, diabetes mellitus, and pregnancy were significantly more frequent among the study patients with carpal tunnel syndrome than in the general population of Rochester, Minnesota. The standardized morbidity ratio was 3.6 for rheumatoid arthritis, 2.3 for diabetes mellitus, and 2.5 for pregnancy. The population attributable risk for pregnancy among women 15 to 44 years old was 7.0%. The standardized morbidity ratio for polymyalgia rheumatica was not significantly increased.
As technology invades the workplace, it appears that more and more cases of carpal tunnel syndrome are surfacing in physician offices. There may be a way to prevent the syndrome, however--simply by examining an employee's wrist.
This is a preliminary report outlining an endoscopic technique to release the carpal ligament employing current arthroscopic methods. The technique has been used successfully on 62 hands in 46 patients with no known complications. In some cases, the follow-up period has been rather short. Based on our results, however, there has been rapid recovery with decreased scarring and postoperative pain and no loss of grip or pinch strength, which is sometimes seen with the conventional method of carpal ligament release.
Skeletal Radiology Skeletal Radiol (1988) 17:85-86 Case report 464 Leanne L. Seeger, M.D., Lawrence W. Bassett, M.D., and Richard H. Gold, M.D. Department of Radiological Sciences, UCLA School of Medicine, Los Angeles, California, USA Radiological studies Fig. 1 A, B. Posteroanterior (A) and carpal tunnel (B) views of the right wrist and hand are demonstrated Fig. 2A, B. Comparison films of the asymptomatic left wrist show features similar to those present on the right. The radiological findings will be described subsequently Clinical information This 28-year-old man presented to the emergency room with pain dorsal to the proximal aspect of the right second and third metacarpals following a fight. No prior history of trauma to the hand or wrist was elicited. Physical examination demon- Address reprint requests to. Leanne L. Seeger, M.D., Depart- ment of Radiological Sciences, UCLA School of Medicine, Los Angeles, CA 90024, USA strated edema and ecchymosis with a human bite- induced laceration on the dorsum of the right third metacarpophalangeal joint. No neurological defi- cits were present and muscle strength was limited only by pain. Roentgenograms of the right wrist and hand were obtained (Fig. 1 A and B). The ra- diological findings were noted to be symmetrical when similar studies of the asymptomatic left wrist and hand (Fig. 2A and B) were obtained. 9 1988 International Skeletal Society
Radiographic confirmation in cases of suspected hook of hamate fractures can be very difficult. Films, including the carpal tunnel view, may be difficult to interpret. We describe a new semisupine oblique radiographic view of the carpus that permits excellent visualization of the hamate hook, is cost efficient, and allows for patient comfort during the study.
We present four cases of carpal bone fractures which were not recognized on standard anteroposterior (AP) and lateral views of the wrist. When there is clinical suspicion of fractures of the hook of the hamate, pisiform, or trapezium, either because of the mechanism of injury or clinical presentation, a carpal tunnel view of the wrist is often helpful to disclose previously unrecognized fractures.
Increasing reports of fractured hamate hooks have provided a sharper focus on causes, diagnosis, treatment, and associated anomalies such as ulnar neuropathy, bipartition, and accessory ossicles. This case report, presenting ulnar tunnel syndrome with bilateral hamulus bipartition, illustrates the relation between these anomalies.
A modified approach to endoscopic carpal tunnel release has been developed and tested in 60 cadaveric specimens by three surgeons using the Agee endoscopic carpal tunnel release system. The modified approach, which includes specific localization of the hook of the hamate, flexor retinaculum, and the superficial palmar arch utilizing topographical landmarks, avoids entry into Guyon's canal and injury to the ulnar artery and nerve, median nerve, and common digital nerves. Use of the anatomic approach resulted in significantly superior results. There were fewer incomplete releases, and fewer surgical passes were required, for the inexperienced surgeons. When these anatomic considerations were not included, the learning curve was much steeper. For surgeons planning endoscopic surgical release of the transverse carpal ligament, the described topographical approach improves the technical competence with the procedure and reduces the number of complications and learning curve associated with new procedures. We recommend the use of topographical landmarks and other anatomic considerations during endoscopic carpal tunnel release.
In the analysis of magnetic resonance (MR) images of the wrist joint, some structural variations may lead to misinterpretation. Our aim was to search for different anatomical variants and their MR characteristics on axial images. Two groups of patients with rheumatoid arthritis (thirty one) and carpal tunnel syndrome (sixty two), and a group of asymptomatic controls (fifty four) underwent bilateral MR axial wrist imaging from the metacarpal bases to the distal radiocarpal joint. The imaging techniques included spin echo (SE), turbo spin echo (TSE) and fast field echo (FFE) sequences, using 3 mm-slice thickness. Different anatomical variants including hypoplasia of the hamulus or hook of the hamate bone (4 cases), anomalous muscles (lumbricals) inside the carpal tunnel (2 cases), unusual location (5 cases) and double branching of the median nerve (14 cases), and aberrant median artery (one case) were detected. These variants, if unfamiliar to MR readers, may be misinterpreted as pathological features.
Endoscopic carpal tunnel release has become an increasingly popular method of surgical treatment of carpal tunnel syndrome. Consequently, the contraindications to this technically challenging procedure continue to evolve. We describe two patients with carpal tunnel syndrome and unusual anomalies and pathology of the hook of the hamate that we believe represent relative or absolute contraindications to endoscopic carpal tunnel release.
The hook of the hamate is an important landmark in endoscopic carpal tunnel release. We studied the incidence of abnormalities of the hook of the hamate in patients with carpal tunnel syndrome. One hundred thirty-one consecutive patients presenting with carpal tunnel syndrome underwent carpal tunnel radiography. Abnormalities of the hook of the hamate were present in 6 of 131 patients (4.6%). The hook of the hamate was aplastic in 3 of 131 patients (2.3%). A bipartite hook of the hamate was present in 1 patient (0.8%). A nonunion of an old fracture of the hook of the hamate was found in two patients (1.6%). The previously reported incidence of an aplastic hook of the hamate in the general population is 1 of 1,452 (0.06%). The odds ratio revealed a 34-fold increase in the risk of hamate abnormalities in the carpal tunnel population (p < 0.001). Hook of the hamate abnormalities may be more common than previously reported.
Normal skeletal variants are a common occurrence in clinical practice and may lead to misinterpretation. As part of a case control study investigating the carpal tunnel, our asymptomatic and voluntary participant underwent magnetic resonance (MR) imaging of both wrists from the metacarpal bases to the distal radiocarpal joint. The imaging techniques included spin echo (SE), turbo spin echo (TSE) and fast field echo (FFE) sequences using 4 mm-slice thickness. As an incidental finding bipartite hamulus was detected bilaterally. The anomaly was evident in both hamuli with similar MRI characteristics. The congenital origin was further supported by the absence of trauma or surgery to the wrists. In this case report the authors discuss the anatomical variant, bilateral bipartite hook of the hamate, and demonstrate the reliability of contiguous slices of MR axial slices in displaying an anatomical variant of the carpus. This normal variant of the hamate is not commonly encountered in MR imaging of the wrist and can be misinterpreted as fracture or post-traumatic sequelae. Images of the normal hamulus are presented for comparison.
Hypothyroidism is commonly included as an important risk factor for carpal tunnel syndrome (CTS), yet no study clearly defines the nature of this association. The purpose of this study was to evaluate the relationship between hypothyroidism and CTS in a controlled study. Twenty-six hypothyroid patients (45 hands) meeting our inclusion criteria with a diagnosis of primary hypothyroidism were questioned regarding date of diagnosis of hypothyroidism, duration and dose of thyroid replacement, and the presence, character, and duration of CTS symptoms. Twenty-four healthy volunteers (47 hands) were used as controls. Clinical examination included sensibility testing with Semmes-Weinstein monofilaments, Weber 2-point discrimination testing, examining for thenar muscle atrophy and weakness, Phalen's test, Tinel's sign at the wrist, and the manual compression test. Electrodiagnostic testing including distal motor latency and distal sensory latency was performed on the median nerve at the wrist on all subjects. Nineteen patients (73%; 31 hands [68%]) displayed symptoms of CTS; of these, 16 patients (25 hands) had clinical examinations consistent with CTS. Only 6 of the 16 patients with clinical CTS (7 of 25 hands) had electrical studies that supported a diagnosis of CTS. All these symptomatic patients were biochemically euthyroid. All control subjects had normal electrical study results and normal sensibility testing. Two subjects had positive clinical examinations, giving a false-positive rate of 4%. Carpal tunnel syndrome symptoms are common in hypothyroid patients even when they are euthyroid. In this group of patients, normal median nerve latencies at the wrist in the presence of CTS symptoms and a positive physical examination are more prevalent than expected by the reported sensitivities of electrodiagnostic testing. Standards for assessing normal median nerve latencies may be significantly different in hypothyroid patients.
Ten intact wrist joints were examined to evaluate the hamate hook visualisation by a hamate hook lateral radiographic view. Results of the study indicated that this 30 degrees -tilted lateral wrist radiographic projection with palmar abduction of the thumb clearly revealed the hamate hook from its base to the tip in the first web space away from the metacarpal bases and carpal bones. This radiographic technique was applied on patients who experienced pain at the hypothenar eminence. Fracture can be detected at the hamate hook in two cases and bilateral bipartite hamulus in one case. This specific supplementary projection is recommended in patients with the relevant physical signs.
Carpal tunnel syndrome (CTS) has been associated frequently with physical factors and personal factors including smoking, obesity, diabetes mellitus, and hypothyroidism. The purpose of this retrospective case-control study was to evaluate the prevalence of personal factors in patients with CTS compared with a normal control group. The charts of 514 patients who underwent a carpal tunnel release procedure and 100 control subjects were examined for history of smoking, obesity, diabetes, and hypothyroidism. Compared with the control subjects, there were significantly less CTS patients who smoked (p < 0.001; odds ratio, 0.17). However, there were more CTS patients than control subjects who were obese (p = 0.02; odds ratio, 1.77), had diabetes (p = 0.03; odds ratio, 3.02), and had hypothyroidism (p = 0.02; odds ratio, 3.70). These results support previous reports that CTS is multifactorial, with such factors as obesity, hypothyroidism, and diabetes but not smoking to be more prevalent in this group of CTS patients.
This study investigated whether there is an association between hand and wrist configurations and the occurrence of carpal tunnel syndrome. The external hand and wrist dimensions of 50 subjects with carpal tunnel syndrome and 50 healthy volunteers were measured and compared. In addition carpal tunnel depth and width were determined with ultrasound. Our results showed that the hand length was significantly higher in the control group (hand length, 19.0; SD, 1.0 cm: patients' hand length, 18.2; SD, 1.1cm) and the palm width was significantly greater in the patients' group (palm width, 9.1; SD, 0.7 cm: controls palm width, 8.6; SD, 0.6 cm). Carpal tunnel syndrome patients had a squarer wrist (wrist ratio, 0.72; SD, 0.1) and carpal tunnel (carpal tunnel ratio, 0.48; SD, 0.1) than the controls (wrist ratio, 0.68; SD, 0.1; carpal tunnel ratio, 0.42; SD, 0.1). These findings indicate that the anatomy of the hand, wrist and carpal tunnel may predispose to carpal tunnel syndrome.
We have undertaken a large case-control study using the UK General Practice Research Database to quantify the relative contributions of the common risk factors for carpal tunnel syndrome (CTS) in the community. Cases were patients with a diagnosis of CTS and, for each, four controls were individually matched by age, sex and general practice. Our dataset included 3,391 cases, of which 2,444 (72%) were women, with a mean age at diagnosis of 46 (range 16-96) years. Multivariate analysis showed that the risk factors associated with CTS were previous wrist fracture (OR=2.29), rheumatoid arthritis (OR=2.23), osteoarthritis of the wrist and carpus (OR=1.89), obesity (OR=2.06), diabetes (OR=1.51), and the use of insulin (OR=1.52), sulphonylureas (OR=1.45), metformin (OR=1.20) and thyroxine (OR=1.36). Smoking, hormone replacement therapy, the combined oral contraceptive pill and oral corticosteroids were not associated with CTS. The results were similar when cases were restricted to those who had undergone carpal tunnel decompression.
In this study we aimed to identify the role of the body mass index (BMI), wrist index and hand anthropometric measures as risk factors for carpal tunnel syndrome (CTS) in both genders. Based on clinical and electrophysiologic diagnostic criteria, 154 female and 44 male CTS patients, as well as 150 female and 44 male age-matched control subjects, were selected. BMI, wrist index, hand shape index, digit index and hand length/height ratio were compared between the CTS patients and the control subjects for each gender separately. Mean BMI was found to be a significant risk factor for CTS in both genders. The wrist index was found to be higher in female (P < 0.001) and in male (P = 0.034) CTS groups than in the respective control groups. Logistic regression analysis revealed the wrist index to be an independent risk factor in females, but not in males. Shape and digit indices were significantly higher in female CTS patients than in corresponding control subjects, and regression analysis showed the shape and digit indices to be independent risk factors for CTS. In the male CTS group, the shape and digit indices did not significantly differ from their controls. Differences in the hand length/height ratio were not statistically significant in female and male CTS patients compared to their controls and it was not found to be an independent risk factor for CTS. Our study confirmed BMI as an independent risk factor for CTS in both genders. Hand and wrist anthropometrics were found to be independent risk factors for CTS in females, but not in males.
The aim of this study was to evaluate the role of gender, body mass index (BMI), wrist ratio (WR) and wrist circumference as independent risk factors for carpal tunnel syndrome (CTS) and to analyze the strength of association of these factors.
We have undertaken a case-control study in 128 CTS patients and 109 controls. Based on clinical and electrophysiologic criteria, 109 female and 19 male CTS patients as well as 62 female and 47 male control subjects were selected from patients and their relatives referred to our hospital. In total, 179 hands with CTS in three groups of severity (mild, moderate and severe) were examined. Height, weight, BMI, wrist width, depth, circumference and ratio were measured in all patients and control group. Mean values of different risk factors for CTS group and controls were measured. A logistic regression analysis was conducted to evaluate odds ratio of different risk factors.
The mean values for BMI and WR were greater in CTS patients than in the subject group. Thirty-four, 89 and 57 patients had mild, moderate and severe CTS, respectively. Mean age, BMI, wrist circumference and ratio were not statistically significant in the three groups. Female gender, increased BMI and increased WR had odds ratio of 9.95, 1.75 and 1.12, respectively.
Our study confirms that female gender, obesity and square wrists are independent risk factors for CTS.
To determine the incidence of anatomic variations of the hook of hamate and to evaluate its association with the development of carpal tunnel syndrome (CTS).
Radiographs of 3,218 hands (2,070 patients) were evaluated. This group included 2,866 hands diagnosed with CTS and 352 hands without the diagnosis of CTS. Using the carpal tunnel view variations of the hook of hamate were identified. Variants were classified based on appearance and measurements. Patients having variant hooks of hamate who were diagnosed with CTS then were compared with patients with variant hooks of hamate who had no evidence of CTS. Endoscopic carpal tunnel release using the Chow technique was performed on all patients with CTS who had a known variation of the hook of hamate without difficulty or complication.
Variations of the hook of hamate were found in 96 hands: 42, bipartite hook; 50, hypoplastic hook; and 4, aplastic hook. Ninety-three hands with variant hooks of hamate were diagnosed with CTS. The remaining 3 hands identified with variants had no evidence of CTS. After comparing the 2 groups, we found that the incidence of a variant hook of hamate in the group with CTS was significantly greater than the incidence of variations in the group without CTS.
Three variations of the hook of hamate were identified with radiographic evaluation using the carpal tunnel view. Variations are more prevalent than once thought. There was a significant increase in the incidence of variation in the hook of hamate in the group with CTS compared with the group without CTS.
Endoscopic carpal tunnel release is gaining increasing acceptance relative to the standard open carpal tunnel release for the treatment of carpal tunnel syndrome. Concerns about endoscopic carpal tunnel release include effectiveness of therapy and complication rates. This study attempted to evaluate outcomes of endoscopic carpal tunnel release in a large patient cohort.
Four hundred eighty-six patients (753 hands) with carpal tunnel syndrome who underwent endoscopic carpal tunnel release by a single surgeon were reviewed retrospectively. Data included demographics, subjective complaints, prior interventions, preoperative examination findings, and postoperative follow-up. All follow-up data were obtained from a single, independent, occupational therapy clinic.
Median patient age was 48 years. Three hundred seventy-seven patients were gainfully employed at presentation, and 206 filed a worker's compensation claim. Median symptom duration was 2 years. Nonoperative therapy was ineffective in 151 patients. Preoperative nerve conduction studies were consistent with carpal tunnel syndrome in 472 patients (97 percent); all patients had either physical examination findings or nerve conduction studies consistent with carpal tunnel syndrome. Four hundred eighty-six patients (100 percent) obtained symptom relief. Complications included one transient median nerve neurapraxia, six complaints of residual pain, and one complaint of hypersensitivity. Worker's compensation patients and non-worker's compensation patients returned to work full-duty at similar times postoperatively. Ninety percent of employed patients returned to their original occupation.
The authors' data indicate that an endoscopic approach for the treatment of carpal tunnel syndrome is safe and effective. Patients demonstrated a high return-to-work rate and an extremely low complication rate. The data challenge the belief that endoscopic carpal tunnel release results in higher complication rates.
To determine if a consensus definition exists in the literature and among hand surgeons for Kaplan's cardinal line (KCL) and to determine the relationship of the various descriptions to deep structures.
The literature contains 4 different descriptions of KCL. Members of the American Society for Surgery of the Hand were surveyed to determine which line they understand to be the correct description of KCL. The 4 variations of KCL were marked on cadavers and the lines' precision in identifying deep structures was measured.
Our survey showed that there is no consensus regarding the definition of KCL. Fifty percent of the surgeons surveyed use KCL as a surgical landmark. A line extended along the abducted thumb and a line from the apex of the interdigital fold between the thumb and the index finger to the hook of hamate most closely reproduce the location of deep structures of the hand and are the farthest from and always proximal to the superficial palmar arch. The line from the apex of the interdigital fold between the thumb and the index finger parallel to the middle crease of the palm and the line from the apex of the interdigital fold between the thumb and the index finger to a point 2 cm distal to the pisiform are the farthest from the motor branch of the median nerve and are markedly closer to the superficial palmar arch. All lines are radial and distal to the motor branch of the median nerve.
Ambiguity exists regarding the definition of KCL among hand surgeons and in the literature. Although no single line is ideal for locating all deep structures, line C is the safest line to identify hand anatomy. Kaplan's cardinal line does not locate the deep structures of the hand accurately but may assist in making palmar incisions.
An evaluation of gender, obesity, age and diabetes mellitus as risk factors for carpal tunnel syndrome.
- Becker J.
- Nora D.B.
- Gomes I.