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Pilonidal Disease and Its Treatment
Pilonidal Disease and Its Treatment CLYDE E. CULP, M.D.
Satisfactory management of pilonidal disease requires not only the surgical procedure suitable for the sinus but also proper aftercare to control any factors that favor redevelopment of the sinus.
ETIOLOGY Although it is rare for a pilonidal sinus to have such an origin, sinuses of the sacrococcygeal region may be congenital. Dimples or short sinuses of this type are usually found to be entirely lined with mature squamous epithelium. The intergluteal cleft is often dry and scaly. The stoma of the sinus is directed cephalad while the tract, if present, is directed caudad. These findings are contrary to those typical of sinuses in the pilonidal state. From his clinicopathologic study of 354 cases at this institution, Franckowiak derived a hypothetical pilonidal habitus: . . . the robust, fat, plethoriC type of male with a narrow pelvis, a deep sulcus between the prominent folds of the thick buttocks, an excessive growth of hair on his back (hypertrichosis), an oily skin caused by excessive glandular activity, and susceptibility to staph infection.
In such a patient the disease is severe and sinuses are likely to recur. It seems that if all pilonidal sinuses were of congenital origin they should be fairly equally distributed between the sexes and the symptoms of pilonidal disease should appear at the same approximate age in the two sexes. However, such symptoms do become evident earlier in the female, probably because of pubertal changes. Also, congenital conditions usually are discovered in the first few months of life rather than in adolescence or young adulthood. Imperfections of other organs are often associated with a congenital anomaly but seldom with pilonidal disease. One of the better arguments in establishing the acquired nature of the sinus is the recurrence of pilonidal disease after surgical treatment. It is difficult to visualize how any congenital defective tissue could have been overlooked in patients who demonstrate a large surgical scar, usually with some degree of fixation to the underlying sacrum. Excisions of this magnitude should have encompassed all the abnormal tissue, in Surgical Clinics of North America- Vol. 47, No.4, August, 1967
1007
1008
CLYDE
E.
CULP
both width and depth. This is especially likely when the disease has recurred for the third or fourth time. We are indebted to Hodges,6.7 who in 1880 described the condition and applied the term "pilonidal" -literally, hair nest. He should likewise be given credit for suspecting the etiology. His explanation was that short, loose hairs from the surface in people of unclean habits, accumulated in a postanal dimple, excoriated the skin and worked their way into deeper tissues, causing a sinus. He noted the condition could be found in other parts of the body and could be caused by hair other than that of the patients. Hair cutters developed interdigital sinuses on their hands - an observation lost until the report of Patey and Scarff15 in 1946. Pilonidal sinuses containing wool,9 grass,12 animal hair, 4and hair of a color different from that of the patient's8 have been reported. In Franckowiak's study, hair was found in 27% of 319 surgical specimens of pilonidal disease. None of the specimens afforded evidence of hair-root structures. Foreign-body giant cells were identified in 44% of the total group of specimens. Frequently the giant cells were grouped about a hair, and it is possible that this feature has given the erroneous impression that a hair follicle was present. Apart from the sacrococcygeal region, the usual places for pilonidal sinuses are where the normally occurring skin folds are exaggeratedsuch as the umbilicus,IO clitoris,13 and axilla, 1 and the sole of the foot.ll Often the local conditions are similar to those in which the sacrococcygeal pilonidal sinuses develop. One should not forget that the local factors mentioned earlier aid the process and are probably the primary reasons why pilonidal disease develops in the sinus. Although the exact mechanism or mechanisms allowing penetration of the hair are unknown, several interesting suggestions have been advanced. Patey and Scarff16 believed that the friction produced by the natal cleft is probably the essential factor in producing the sinus. Brearley postulated that the hair becomes clustered in drill-like form which enters the skin, and that with shedding, the hairs are sucked further into the sinus, thus increasing its extent. Palmer14 reported that there is stretching of the integument at puberty which produces sufficient spreading of the orifices of the skin to allow the insinuation of foreign substances. Franckowiak concluded from his study that recurrent pilonidal disease did not result from failure to remove all of the abnormal tissues. He thought that recurrence was more often due to (1) poor surgical judgment in the selection of the operative procedure, (2) failure to eliminate completely the local and general predisposing conditions that existed when the sinus was formed, and (3) inadequate postoperative care-that being probably the most important factor.
SURGICAL PROCEDURE In our opinion, primary closure invites recurrence, except in a few carefully selected cases. The multitude of methods for wound closure
PILONIDAL DISEASE AND ITS TREATMENT
1009
in the literature of pilonidal disease is a testament to the difficulty of eliIninating the dead space. Practically always the site of a recurrent sinus is between the scars from the last two distal sutures. The correction of local and general factors is an important part of the surgical aftercare. Actually, the preparation is begun at the time the patient is first seen. He should be apprised of the probable cause of his condition and impressed with the importance of frequent follow-up exaIninations. Attempts to correct poor local hygiene are undertaken, and measures against obesity if that is present. Buie and Curtiss reported a marsupialization technique utilized in the management of pilonidal difficulties. A siInilar basic plan is still followed with some individual modifications. The sinus may be excised or exteriorized. The latter is my preference because the lateral dissection is under better control, allowing the development of a wound which facilitates its postoperative care. Introduction of a probe into each of the sinus openings deterInines the depth and extent of the involvement. The overlying tissues are incised, revealing the granulation tissue lining the exposed tract (Fig. 1). Removal of the gelatinous tissue is best accomplished with a dermal
Figure 1. Probe delineates extent of pilonidal cavity. and overlying tissues are incised with probe as guide.
1010
CLYDE
E.
CULP
Figure 2. Granulation tissue and hair are removed by curet, leaving clean fibroustissue base. Inset, Contour of wound.
curet (Fig. 2). Offshoots from the main tract are easily demarcated by the presence of granulation tissue. These are probed and opened as necessary. Lateral dissection of the skin is accomplished by use of scissors. The desired final result is a flattened shallow wound with sloping edges. Each extremity of the wound is rounded off in such a degree that its healing will more closely coincide with that of the midportion of the wound (Fig. 3). This maneuver prevents apposition of the wound edges as the buttocks fall together if the dressing should become displaced. The resultant bridging would produce incomplete healing with a weakened scar, much as is seen in recurrent sinuses in the primarily closed wound. The white fibrous tissue of the sinus tract is joined to the cut edge of the skin with a continuous locking suture of plain 2-0 catgut (Fig. 4). Although the suture is primarily for hemostasis, it can be of great aid, if judiciously applied, in reducing the extent of the wound both horizontally and vertically (Fig. 5). The aggregate diameter of the wound may be reduced by 50 to 60% without excessive tension on the skin edges. Additional hemostasis is obtained by the pressure dressing. Adherence of the gauze is prevented by placement within the wound of a
PILONIDAL DISEASE AND ITS TREATMENT
1011
Figure 3. Adjacent tissues are excised obliquely to form exteriorized wound with sloping edges. Inset, Contour of wound.
piece of rubber glove from which the fingers have been removed. Several squares of gauze are rolled individually and placed into the rubber-lined cavity. Large squares are fluffed and are applied in such manner that they overlap the wound edges by several inches. Gauze is then made into a roll of sufficient diameter to exert pressure upon the wound and its edges when the elastic adhesive bandage is applied (Fig. 6).
AFTER-TREATMENT Removal of the dressing in 48 hours is not traumatic to the wound or the patient. In fact, the rubber glove is used in the majority of anorectal procedures at this clinic. Daily inspection of the wound is essential to the prevention of fibrinous bridges. The wound is often quite moist and the adjacent skin may become irritated. After a bath or shower, dry heat is applied by means of a lamp or a hair dryer. (The latter method was suggested by Capt. Paul Sebrechts of the United States Navy.) As hair appears adjacent to or in the skin edges of the wound, it is clipped away or better still removed with depilating forceps.
1012
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E.
CULP
Figure 4. Edges of fibrous-tissue base are sutured to skin edges for hemostasis, also flattening wound and decreasing overall dimensions. Inset, Contour of wound.
Figure 5. Completion of suturing that exteriorizes pilonidal wound.
PILONIDAL DISEASE AND ITS TREATMENT
1013
PRESSURE DRESSING: elastic adhesive rge gauze roll loose gauze uze roll rubber
Figure 6.
Diagram of final pressure dressing.
Gauze squares are fluffed up and placed in the wound to keep its edges separated and the base as flat as possible. The dressings are maintained in this position by underwear of the brief type, obviating the fixation to the skin by adhesive materials and the resultant irritation accompanying frequent changes of dressing. Hospital dismissal is often possible on the fifth to the seventh day. This depends upon the wound size but more particularly on the patient's ability to understand the care of his wound. At home he can apply dry heat via the flexible hose of the hair dryer. It is stressed that he should separate the wound edges and apply the fluffed gauze directly into the wound as the surgeon has done at each daily office visit. The surgeon levels tufts of excess granulation tissue to the general contour of the wound with scissors or small dermal curet. Hair is removed as it appears; it may be wise to shave the general area every 10 to 14 days. As epithelization of the developing scar becomes established, the surgeon seeks soft or honeycombed parts of it and defines them by palpation of the entire area with a cotton-tipped applicator. If too forceful application of tension on the skin adjacent to the healing area causes splitting of the newly acquired surface, such defects are saucerized with sharp scissors. Ordinarily a patient with a white-collar job can return to work 2 weeks after the surgical procedure; those engaged in heavy labor are held up an additional week. The surgeon continues to inspect the wound every other day until healing is complete. It is wise to check the integrity of the new scar once or twice more at intervals of 3 to 5 days before completely dismissing the patient. The importance of final instructions to the patient cannot be overemphasized. Local hygiene is stressed once again. Shaving or depilating the area contiguous to the scar every 14 to 21 days, depending upon the rapidity of hair growth, is recommended. A bath or shower each morning and upon return from work in the evening is suggested. After thorough drying of the sacrococcygeal region, a large pledget of cotton should be
1014
CLYDE
E.
CULP
placed in the natal cleft, thus separating the thick buttocks to allow free circulation of air. The cotton takes up excess moisture, preventing maceration of the surface of the scar. Efforts at weight reduction, which was begun as a hospital program, should be continued by an active dietary regimen. The patient should be encouraged to return to the surgeon whenever he becomes suspicious of the integrity of the operative scar in the sacrococcygeal area. Small defects, tiny abscesses, and short recurrent sinuses can be cared for in the office with a minimum of effort obviating further prolonged disability for the patient.
SUMMARY Pilonidal disease is an acquired condition affecting predominantly hirsute, obese, young adult males. The open method of surgical management is favored. Correction of local conditions and frequent observations of the healing wound are important phases of treatment.
REFERENCES 1. Aird, I.: Pilonidal sinus of the axilla. Brit Med J 1 :902-903 (April 26) 1952. 2. Brearley, R.: Pilonidal sinus: A new theory of origin. Brit J Surg 43:62-68 (July) 1955. 3. Buie, L. A., and Curtiss, R. K.: Pilonidal disease. Surg Clin N Amer 32:1247-1259 (Aug.) 1952. 4. Currie, A. R., and Bonar, A. A.: Interdigital fistula of foot in a worker in a hair mattress factory. Glasgow Med J 36:136-137 (April) 1955. 5. Franckowiak, J. J.: The etiology of pilonidal sinus. Thesis, Graduate School, University of Minnesota, 1960. 6. Hodges, R. M.: Pilo-nidal sinus. Boston Med Surg J 103:485-486 (Nov. 11) 1880. 7. Hodges, R. M.: Discussion. Boston Med Surg J 103:493 (Nov. 18); 544 (Dec. 2) 1880. 8. King, E. S. J.: Interdigital pilonidal sinus. Aust New Zeal J Surg 19:29-33 (Aug.) 1949. 9. Matheson, A. D.: Interdigital pilonidal sinus caused by wool. Aust New Zeal J Surg 21 :76-77 (Aug.) 1951.10. Mayo, C. W., Franckowiak, J. J., and Dockerty, M. B.: Pilonidal sinus of the umbilicus: Report of case. Proc Staff Meet Mayo Clin 35: 175-178 (March 30) 1960. 11. Morrell, J. F.: Pilonidal sinus of the sole. Arch Derm (Chicago) 75:269 (Feb.) 1957. 12. Page, B. H.: The hair of the pilonidal sinus. (Letter to the editor.) Lancet 1 :873 (April 23) 1955. 13. Palmer, E.: Pilonidal cyst of the clitoris. Amer J Surg 93:133-136 (Jan.) 1957. 14. Palmer, W. H.: Pilonidal disease: A new concept of pathogenesis. Dis Colon Rectum 2 :303-307 (May-June) 1959. 15. Patey, D. H., and Scarff, R. W.: Pathology of postanal sinus: Its bearing on treatment. Lancet 2:484-486 (Oct. 5) 1946. 16. Patey, D. H., and Scarff, R. W.: The hair of the pilonidal sinus. (Letter to the editor.) Lancet 1:772-773 (April 9) 1955.
Satisfactory management of pilonidal disease requires not only the surgical procedure suitable for the sinus but also proper aftercare to control any factors that favor redevelopment of the sinus.
ETIOLOGY Although it is rare for a pilonidal sinus to have such an origin, sinuses of the sacrococcygeal region may be congenital. Dimples or short sinuses of this type are usually found to be entirely lined with mature squamous epithelium. The intergluteal cleft is often dry and scaly. The stoma of the sinus is directed cephalad while the tract, if present, is directed caudad. These findings are contrary to those typical of sinuses in the pilonidal state. From his clinicopathologic study of 354 cases at this institution, Franckowiak derived a hypothetical pilonidal habitus: . . . the robust, fat, plethoriC type of male with a narrow pelvis, a deep sulcus between the prominent folds of the thick buttocks, an excessive growth of hair on his back (hypertrichosis), an oily skin caused by excessive glandular activity, and susceptibility to staph infection.
In such a patient the disease is severe and sinuses are likely to recur. It seems that if all pilonidal sinuses were of congenital origin they should be fairly equally distributed between the sexes and the symptoms of pilonidal disease should appear at the same approximate age in the two sexes. However, such symptoms do become evident earlier in the female, probably because of pubertal changes. Also, congenital conditions usually are discovered in the first few months of life rather than in adolescence or young adulthood. Imperfections of other organs are often associated with a congenital anomaly but seldom with pilonidal disease. One of the better arguments in establishing the acquired nature of the sinus is the recurrence of pilonidal disease after surgical treatment. It is difficult to visualize how any congenital defective tissue could have been overlooked in patients who demonstrate a large surgical scar, usually with some degree of fixation to the underlying sacrum. Excisions of this magnitude should have encompassed all the abnormal tissue, in Surgical Clinics of North America- Vol. 47, No.4, August, 1967
1007
1008
CLYDE
E.
CULP
both width and depth. This is especially likely when the disease has recurred for the third or fourth time. We are indebted to Hodges,6.7 who in 1880 described the condition and applied the term "pilonidal" -literally, hair nest. He should likewise be given credit for suspecting the etiology. His explanation was that short, loose hairs from the surface in people of unclean habits, accumulated in a postanal dimple, excoriated the skin and worked their way into deeper tissues, causing a sinus. He noted the condition could be found in other parts of the body and could be caused by hair other than that of the patients. Hair cutters developed interdigital sinuses on their hands - an observation lost until the report of Patey and Scarff15 in 1946. Pilonidal sinuses containing wool,9 grass,12 animal hair, 4and hair of a color different from that of the patient's8 have been reported. In Franckowiak's study, hair was found in 27% of 319 surgical specimens of pilonidal disease. None of the specimens afforded evidence of hair-root structures. Foreign-body giant cells were identified in 44% of the total group of specimens. Frequently the giant cells were grouped about a hair, and it is possible that this feature has given the erroneous impression that a hair follicle was present. Apart from the sacrococcygeal region, the usual places for pilonidal sinuses are where the normally occurring skin folds are exaggeratedsuch as the umbilicus,IO clitoris,13 and axilla, 1 and the sole of the foot.ll Often the local conditions are similar to those in which the sacrococcygeal pilonidal sinuses develop. One should not forget that the local factors mentioned earlier aid the process and are probably the primary reasons why pilonidal disease develops in the sinus. Although the exact mechanism or mechanisms allowing penetration of the hair are unknown, several interesting suggestions have been advanced. Patey and Scarff16 believed that the friction produced by the natal cleft is probably the essential factor in producing the sinus. Brearley postulated that the hair becomes clustered in drill-like form which enters the skin, and that with shedding, the hairs are sucked further into the sinus, thus increasing its extent. Palmer14 reported that there is stretching of the integument at puberty which produces sufficient spreading of the orifices of the skin to allow the insinuation of foreign substances. Franckowiak concluded from his study that recurrent pilonidal disease did not result from failure to remove all of the abnormal tissues. He thought that recurrence was more often due to (1) poor surgical judgment in the selection of the operative procedure, (2) failure to eliminate completely the local and general predisposing conditions that existed when the sinus was formed, and (3) inadequate postoperative care-that being probably the most important factor.
SURGICAL PROCEDURE In our opinion, primary closure invites recurrence, except in a few carefully selected cases. The multitude of methods for wound closure
PILONIDAL DISEASE AND ITS TREATMENT
1009
in the literature of pilonidal disease is a testament to the difficulty of eliIninating the dead space. Practically always the site of a recurrent sinus is between the scars from the last two distal sutures. The correction of local and general factors is an important part of the surgical aftercare. Actually, the preparation is begun at the time the patient is first seen. He should be apprised of the probable cause of his condition and impressed with the importance of frequent follow-up exaIninations. Attempts to correct poor local hygiene are undertaken, and measures against obesity if that is present. Buie and Curtiss reported a marsupialization technique utilized in the management of pilonidal difficulties. A siInilar basic plan is still followed with some individual modifications. The sinus may be excised or exteriorized. The latter is my preference because the lateral dissection is under better control, allowing the development of a wound which facilitates its postoperative care. Introduction of a probe into each of the sinus openings deterInines the depth and extent of the involvement. The overlying tissues are incised, revealing the granulation tissue lining the exposed tract (Fig. 1). Removal of the gelatinous tissue is best accomplished with a dermal
Figure 1. Probe delineates extent of pilonidal cavity. and overlying tissues are incised with probe as guide.
1010
CLYDE
E.
CULP
Figure 2. Granulation tissue and hair are removed by curet, leaving clean fibroustissue base. Inset, Contour of wound.
curet (Fig. 2). Offshoots from the main tract are easily demarcated by the presence of granulation tissue. These are probed and opened as necessary. Lateral dissection of the skin is accomplished by use of scissors. The desired final result is a flattened shallow wound with sloping edges. Each extremity of the wound is rounded off in such a degree that its healing will more closely coincide with that of the midportion of the wound (Fig. 3). This maneuver prevents apposition of the wound edges as the buttocks fall together if the dressing should become displaced. The resultant bridging would produce incomplete healing with a weakened scar, much as is seen in recurrent sinuses in the primarily closed wound. The white fibrous tissue of the sinus tract is joined to the cut edge of the skin with a continuous locking suture of plain 2-0 catgut (Fig. 4). Although the suture is primarily for hemostasis, it can be of great aid, if judiciously applied, in reducing the extent of the wound both horizontally and vertically (Fig. 5). The aggregate diameter of the wound may be reduced by 50 to 60% without excessive tension on the skin edges. Additional hemostasis is obtained by the pressure dressing. Adherence of the gauze is prevented by placement within the wound of a
PILONIDAL DISEASE AND ITS TREATMENT
1011
Figure 3. Adjacent tissues are excised obliquely to form exteriorized wound with sloping edges. Inset, Contour of wound.
piece of rubber glove from which the fingers have been removed. Several squares of gauze are rolled individually and placed into the rubber-lined cavity. Large squares are fluffed and are applied in such manner that they overlap the wound edges by several inches. Gauze is then made into a roll of sufficient diameter to exert pressure upon the wound and its edges when the elastic adhesive bandage is applied (Fig. 6).
AFTER-TREATMENT Removal of the dressing in 48 hours is not traumatic to the wound or the patient. In fact, the rubber glove is used in the majority of anorectal procedures at this clinic. Daily inspection of the wound is essential to the prevention of fibrinous bridges. The wound is often quite moist and the adjacent skin may become irritated. After a bath or shower, dry heat is applied by means of a lamp or a hair dryer. (The latter method was suggested by Capt. Paul Sebrechts of the United States Navy.) As hair appears adjacent to or in the skin edges of the wound, it is clipped away or better still removed with depilating forceps.
1012
CLYDE
E.
CULP
Figure 4. Edges of fibrous-tissue base are sutured to skin edges for hemostasis, also flattening wound and decreasing overall dimensions. Inset, Contour of wound.
Figure 5. Completion of suturing that exteriorizes pilonidal wound.
PILONIDAL DISEASE AND ITS TREATMENT
1013
PRESSURE DRESSING: elastic adhesive rge gauze roll loose gauze uze roll rubber
Figure 6.
Diagram of final pressure dressing.
Gauze squares are fluffed up and placed in the wound to keep its edges separated and the base as flat as possible. The dressings are maintained in this position by underwear of the brief type, obviating the fixation to the skin by adhesive materials and the resultant irritation accompanying frequent changes of dressing. Hospital dismissal is often possible on the fifth to the seventh day. This depends upon the wound size but more particularly on the patient's ability to understand the care of his wound. At home he can apply dry heat via the flexible hose of the hair dryer. It is stressed that he should separate the wound edges and apply the fluffed gauze directly into the wound as the surgeon has done at each daily office visit. The surgeon levels tufts of excess granulation tissue to the general contour of the wound with scissors or small dermal curet. Hair is removed as it appears; it may be wise to shave the general area every 10 to 14 days. As epithelization of the developing scar becomes established, the surgeon seeks soft or honeycombed parts of it and defines them by palpation of the entire area with a cotton-tipped applicator. If too forceful application of tension on the skin adjacent to the healing area causes splitting of the newly acquired surface, such defects are saucerized with sharp scissors. Ordinarily a patient with a white-collar job can return to work 2 weeks after the surgical procedure; those engaged in heavy labor are held up an additional week. The surgeon continues to inspect the wound every other day until healing is complete. It is wise to check the integrity of the new scar once or twice more at intervals of 3 to 5 days before completely dismissing the patient. The importance of final instructions to the patient cannot be overemphasized. Local hygiene is stressed once again. Shaving or depilating the area contiguous to the scar every 14 to 21 days, depending upon the rapidity of hair growth, is recommended. A bath or shower each morning and upon return from work in the evening is suggested. After thorough drying of the sacrococcygeal region, a large pledget of cotton should be
1014
CLYDE
E.
CULP
placed in the natal cleft, thus separating the thick buttocks to allow free circulation of air. The cotton takes up excess moisture, preventing maceration of the surface of the scar. Efforts at weight reduction, which was begun as a hospital program, should be continued by an active dietary regimen. The patient should be encouraged to return to the surgeon whenever he becomes suspicious of the integrity of the operative scar in the sacrococcygeal area. Small defects, tiny abscesses, and short recurrent sinuses can be cared for in the office with a minimum of effort obviating further prolonged disability for the patient.
SUMMARY Pilonidal disease is an acquired condition affecting predominantly hirsute, obese, young adult males. The open method of surgical management is favored. Correction of local conditions and frequent observations of the healing wound are important phases of treatment.
REFERENCES 1. Aird, I.: Pilonidal sinus of the axilla. Brit Med J 1 :902-903 (April 26) 1952. 2. Brearley, R.: Pilonidal sinus: A new theory of origin. Brit J Surg 43:62-68 (July) 1955. 3. Buie, L. A., and Curtiss, R. K.: Pilonidal disease. Surg Clin N Amer 32:1247-1259 (Aug.) 1952. 4. Currie, A. R., and Bonar, A. A.: Interdigital fistula of foot in a worker in a hair mattress factory. Glasgow Med J 36:136-137 (April) 1955. 5. Franckowiak, J. J.: The etiology of pilonidal sinus. Thesis, Graduate School, University of Minnesota, 1960. 6. Hodges, R. M.: Pilo-nidal sinus. Boston Med Surg J 103:485-486 (Nov. 11) 1880. 7. Hodges, R. M.: Discussion. Boston Med Surg J 103:493 (Nov. 18); 544 (Dec. 2) 1880. 8. King, E. S. J.: Interdigital pilonidal sinus. Aust New Zeal J Surg 19:29-33 (Aug.) 1949. 9. Matheson, A. D.: Interdigital pilonidal sinus caused by wool. Aust New Zeal J Surg 21 :76-77 (Aug.) 1951.10. Mayo, C. W., Franckowiak, J. J., and Dockerty, M. B.: Pilonidal sinus of the umbilicus: Report of case. Proc Staff Meet Mayo Clin 35: 175-178 (March 30) 1960. 11. Morrell, J. F.: Pilonidal sinus of the sole. Arch Derm (Chicago) 75:269 (Feb.) 1957. 12. Page, B. H.: The hair of the pilonidal sinus. (Letter to the editor.) Lancet 1 :873 (April 23) 1955. 13. Palmer, E.: Pilonidal cyst of the clitoris. Amer J Surg 93:133-136 (Jan.) 1957. 14. Palmer, W. H.: Pilonidal disease: A new concept of pathogenesis. Dis Colon Rectum 2 :303-307 (May-June) 1959. 15. Patey, D. H., and Scarff, R. W.: Pathology of postanal sinus: Its bearing on treatment. Lancet 2:484-486 (Oct. 5) 1946. 16. Patey, D. H., and Scarff, R. W.: The hair of the pilonidal sinus. (Letter to the editor.) Lancet 1:772-773 (April 9) 1955.