Nerve tumors of the hand and forearm.

Peripheral nerve tumors comprise less than 5% of all tumors of the hand. The most common solitary nerve tumor is the neurilemmoma, which arises from the neural sheath, is well encapsulated, minimally symptomatic, and may be surgically enucleated without producing a neurological deficit. Neurofibromas may be solitary, multiple, or associated with von Recklinghausen's disease. They are usually centrally placed with nerve fibers traversing the tumor mass making it more difficult to remove the tumor without producing permanent neurological damage. Malignant tumors include neurofibrosarcomas which often are very aggressive, requiring wide excision or amputation, and the rare neuroepitheliomas. Reported nerve tumors, intraneural in location but nonneural in origin, include fibrofatty infiltration of the median and digital nerves, intraneural lipoma, hemangioma, and ganglion cysts. These lesions may be treated by decompression or excision, depending on the nature of the tumor. Four unusual cases are described.     

Benign nerve tumors of the hand and the forearm

We used a hand surgeon's 1978-1994 pathology reports to retrospectively review the incidence, preoperative and postoperative diagnoses, and presenting signs and symptoms of benign nerve tumors. Twenty-four (11.5%) of our series of 208 soft-tissue tumors of the hand and the forearm were benign nerve tumors. Nerve tumors were the third most common tumor after giant cell tumors of tendon sheath and inclusion cysts. Correct preoperative diagnosis was made in only 1 (4.2%) of the 24 cases. Schwannomas and neurofibromas were equally distributed (12 each), and 2 cases of neurofibromatosis (8.3%) were documented. Two (16.7%) of the 12 patients with schwannomas and 4 (33.3%) of the 12 patients with neurofibromas had neurologic symptoms. Six (85.7%) of the 7 digital tumors were dorsally located. In the literature, incidence of benign nerve tumors is much lower (ie, 1%-5%), and preoperative diagnosis consistently incorrect in our study. Incidence of neurologic symptoms (numbness, paresthesia) as presenting symptoms was higher in our study than previously documented. Although benign nerve tumors are most often located on the volar surface of the hand, 25% of the lesions we found were on the dorsal surface of the fingers.     

Selective measurement of digital nerve conduction velocity

We developed a new method to measure the nerve conduction velocity of a single digital nerve. In 27 volunteers (27 hands), we separately stimulated each digital nerve on the radial and ulnar sides of the middle and ring fingers. A double-peaked potential was recorded above the median nerve at the wrist joint when either the radial-side nerve or the ulnar-side nerve of the middle finger was stimulated. The first peak of this potential had disappeared after the digital nerve was blocked under the stimulating electrodes, and the peak appeared again coinciding with the decrease of anesthesia. Shifting the stimulating electrodes on the digital nerve resulted in no significant difference in the peak conduction velocity. It is possible that each peak of the potential was attributable to conduction of an action potential along one of the two digital nerves. This new method allows the assessment of a single digital nerve, and may be clinically useful for assessing the rupture of a digital nerve and the sensory nerve action potentials in carpal tunnel syndrome. Received: June 30, 2000 / Accepted: November 20, 2000     

A modified reversed digital island flap incorporating the proper digital nerve

A standard reversed digital artery flap is based on the digital artery and vena comitantes alone, leaving the proper digital nerve intact. In the authors' opinion, in situations in which the fingertip pulp is lost completely, it is unnecessary to leave the nerve in situ. Using their technique, the proper digital nerve is included in the pedicle. The pedicle is raised as a monobloc of fatty tissue containing the small veins important for drainage. The proper digital nerve in the flap is sutured to the stump of the opposite proper digital nerve. They found this flap to be very reliable, and quite easy and quick to raise. A patient is presented and discussed in detail.     

不同术式的指动脉逆行岛状皮瓣修复指腹缺损及术后感觉功能评价

我院自１９９２年到今，采用三种术式的指动脉逆行岛状皮瓣；（１）吻合神经的：（２）不带神经支的；（３）带指神经血管束的；共急诊修复６８例８２指的手指未节指腹缺损。通过术后２年的随访，对其感觉功能按英国医学研究会标准作了评价。通过比较认为吻合神经的指动脉蒂塑行岛状皮瓣因其解剖方便，血供可靠，术后感觉功能恢复好等优点而成为急诊修复手指未节指腹缺损的最佳术式。     

不同术式的指动脉逆行岛状皮瓣修复指腹缺损及术后感觉功能评价

我院自１９９２年到今，采用三种术式的指动脉逆行岛状皮瓣：（１）吻合神经的；（２）不带神经支的；（３）带指神经血管束的；共急诊修复６８例８２指的手指末节指腹缺损。通过术后２年随访，对其感觉功能按英国医学研究会标准作了评价。通过比较认为吻合神经的指动脉蒂逆行岛状皮瓣因其解剖方便，血供可靠，术后感觉功能恢复好等优点而成为急诊修复手指末节指腹缺损的最佳术式。     

Assessment of nerve graft donor sites used for reconstruction of traumatic digital nerve defects

Several donor nerve graft sites commonly are used when repairing segmental defects in sensory nerves distal to the wrist. The cross-sectional area and number of fascicles of donor nerves and specific digital nerve segments were investigated to provide guidelines for selection of nerve graft harvest sites according to defects encountered. Nerve segments were harvested from 10 fresh cadavers (20 upper extremities). Five sites of nerve graft were harvested: lateral and medial antebrachial cutaneous nerves (LABCN, MABCN), posterior and anterior interosseous nerves (PIN, AIN), and sural nerves. Four sites of typical segmental nerve defects were harvested in a zone protocol: common digital nerve (zone 4), proper digital nerve (zone 3), digital nerve distal to main dorsal branch at the metacarpophalangeal joint (zone 2), and digital nerve distal to trifurcation at fingertip (zone 1). Sural nerve is the most anatomically similar nerve graft for defects in zone 4 by cross-sectional area and number of fascicles. Lateral antebrachial cutaneous nerve is most appropriate for zone 2 and 3 injuries by both criteria. Fingertip grafts for zone 1 injuries displayed cross-sectional area similarity to PIN, AIN, and MABCN. With regard to number of fascicles, zone 1 digital nerves are most similar to LABCN donors.     

指固有神经背侧支移位重建指腹感觉功能

目的 介绍示中环指指固有神经背侧支移位,修复同指对侧指固有神经或邻指指固有神经撕脱离断伤的方法.方法 2003年8月至2008年12月,对56例72指指固有神经撕脱离断伤患者,取同指对侧或邻指相邻侧指固有神经背侧支移位,与受损指固有神经远断端缝合修复.结果 术后56例均获得6个月至1.5年的随访,平均1年2个月.修复侧指腹感觉均恢复,两点分辨觉为6～9 mm(平均7.3 mm),感觉为S4.指腹饱满.结论 示中环指指固有神经背侧支移位,修复同指对侧指固有神经或邻指指固有神经撕脱离断伤的方法,能恢复指腹良好感觉,方法简单,疗效确切.

Abstract：

Objective To introduce the surgical method of transferring dorsal branch of the proper digital nerve of index, middle or ring finger to the lacerated digital nerve on the opposite side of the same finger or the neighboring finger. Methods From August 2003 to December 2008, 72 lacerated proper digital nerves in 56 cases were repaired by transferring dorsal branch of the proper digital nerve from the opposite side of the same finger or from the neighboring side of the neighboring finger. The transferred nerve was coapted to the distal end of the lacerated nerve. Results All 56 cases were followed for 6 months to 1.5 years postoperatively, with an average of 14 months. Recovery of sensation of the reinnervated finger pulps was observed in all cases. Two-point discrimination was 6 to 9 mm, average being 7.3 mm. Sensory function was rated as S4. The pulps were full in contour. Conclusion Transferring dorsal branch of the proper digital nerve of index, middle or ring finger to the lacerated digital nerve on the opposite side of the same finger or the neighboring finger was a simple and effective method to restore sensory function of the pulp.     

Digital nerve grafting using the dorsal sensory branch of the ulnar nerve

The dorsal sensory branch of the ulnar nerve has been found to have the appropriate size and sufficient length for use as a digital nerve graft. This donor nerve was utilised fifteen times in twelve patients for the bridging of defects in thirteen digital nerves of the fingers. After an average follow-up of 23.2 months, only one patient failed to achieve any two point discrimination in the area supplied by the involved digital nerve. The other eleven patients had an average two point discrimination of 9.5 mm with a range of 5 to 18 mm. Painful neuroma formation or loss of hand function related to the use of the dorsal sensory branch of the ulnar nerve as a donor for digital nerve grafts was not encountered.     

Compression neuropathy of the radial palmar thumb nerve

Compression neuropathy of a single digital nerve is a rare entity. We report the case of a patient with numbness in the distribution of the radial digital nerve of the thumb caused by the use of a walking stick. The nerve was compressed between the handle of the stick, the loop and the radial sesamoid bone of the first metacarpophalangeal joint. The site of the lesion was confirmed by electrophysiologic examination. Orthodromic recording of the sensory response from the radial palmar digital nerve of the thumb documented a complete absence of nerve action potential whereas the ulnar digital thumb nerve showed a normal response. Sensory function was restored when a padded ski glove was used to protect the area of the metacarpophalangeal joint whilst using the stick.     

Crossover innervation after digital nerve injury: myth or reality?

Several clinical studies promulgate the concept that some degree of crossover innervation occurs after digital nerve injuries are sustained and that the intact digital nerve might even substitute for the loss of nerve function on the injured side. Other studies strongly dispute the existence of this phenomenon. An excellent model for evaluation of crossover innervation is bilateral sharp digital nerve lacerations because there is no confusion of anomalous innervation from an intact contralateral nerve. This model avoids problems seen with replanted digits such as the inherent ischemia, multistructural injury, and the frequent crush component. The author evaluates the role of crossover innervation after digital nerve injury by comparing recovery of sensibility after unilateral and bilateral epineural neurorrhaphies. A retrospective review of 74 sharp unilateral and bilateral epineural digital nerve repairs in 54 patients using microsurgical techniques was performed by measurement of Weber's two-point discrimination (2PD). Fifty-four unilateral digital nerve repairs were performed in 46 patients who ranged in age from 8 to 54 years (mean age, 30.8 years). Concomitant flexor tendon injuries occurred in 50% of patients. Injury to repair was less than 1 day in 14.3% of patients, 2 to 7 days in 34.7%, 8 to 30 days in 40.8%, and 31 to 300 days in 10.2%. Follow-up ranged from 6 to 68 months (average follow-up, 13.8 months). Twenty bilateral digital nerve repairs were performed in 8 patients who ranged in age from 6 to 37 years (mean age, 27.6 years). Concomitant flexor tendon injuries occurred in 80% of patients. Injury to repair was less than 1 day in 10% of patients, 2 to 7 days in 60%, 8 to 30 days in 20%, and 31 to 300 days in 10%. Follow-up ranged from 6 to 77 months (average follow-up, 15.8 months). In this series, 2PD averaged 7.8 mm after unilateral digital nerve repairs compared with 7.1 mm after bilateral nerve repairs. Recovery of sensibility was also stratified into groups according to modified American Society for Surgery of the Hand guidelines: excellent, <6 mm; good, 6 to 10 mm; fair, 11 to 15 mm; and poor, >15 mm or protective sensation. Unilateral digital nerve repairs produced excellent results in 27.8% of patients, good in 46.3%, and fair in 25.9% compared with bilateral nerve repairs with excellent results in 15% of patients, good in 70%, and fair in 15%. There was no significant difference in recovery of sensibility after unilateral and bilateral digital nerve repairs. Crossover innervation did not appear to influence the long-term outcome after digital neurorrhaphy.     

Anatomic study of the ramus communicans between the ulnar and median nerves

The communicating branch between the fourth and third common digital nerves in the palm of the hand was studied. The incidence and branching pattern were studied in 53 dissected cadaveric hands. The "danger zone" in which the nerve is at risk during surgery was established using morphometric data. A communicating branch was found in 50 hands. It originated proximally from the fourth common digital nerve to join the third common digital nerve distally in 44 hands and traversed perpendicularly between the third and fourth common digital nerves in 4 hands. In the 2 remaining hands the branch left the third common digital nerve proximally to join the fourth digital common nerve distally. In 90% of the hands the ramus communicans crossed over in the middle third of the palm of the hand. As a cautious measure, hand surgeons should take into account that this structure could cross over anywhere in the middle three fifths of the palm.     

End-to-side repair of thenar motor branch of median nerve to the ulnar nerve after excision of the median nerve neurofibroma

A 13-year-old male patient suffering for the past 5 years with a gradually swelling and occasionally painful volar side of right forearm, presented to our clinic without any trauma. An end-to-side nerve repair performed between the ulnar nerve and thenar motor branch, and second common digital nerve to the digital nerve of the first finger for mend the sensorial, digital, and motor impairments related to the median nerve associated plexiform neurofibroma that occured after the excision of the tumor.     

Benign spinal nerve sheath tumors: their occurrence sporadically and in neurofibromatosis types 1 and 2.

Benign spinal nerve sheath tumors (neurofibromas and schwannomas) often occur on dorsal nerve roots sporadically or in neurofibromatosis types 1 and 2. These are histologically benign tumors, and distinction between them is frequently not made by clinicians. To determine if there is a correlation between the histological pattern of benign spinal nerve sheath tumors and the type of neurofibromatosis, the clinical and pathological features of these tumors (86 surgical specimens and five autopsies) in 68 patients were reviewed. The patients were classified into one of four categories: neurofibromatosis type 1, neurofibromatosis type 2, uncertain, or sporadic. The diagnostic criteria used for neurofibromatosis types 1 and 2 were established by the National Institutes of Health. Patients who did not fulfill criteria for either neurofibromatosis type 1 or 2 but who had multiple nervous system tumors or other stigmata of neurofibromatosis were designated "uncertain." Spinal nerve sheath tumors were considered sporadic in 42 cases (40 schwannomas and two neurofibromas). In the 14 patients with neurofibromatosis type 1, all spinal nerve sheath tumors were neurofibromas. In six of the seven patients with neurofibromatosis type 2, all spinal nerve sheath tumors were schwannomas. One patient with neurofibromatosis type 2 had a spinal nerve sheath schwannoma and a tumor with features of both tumor types. The authors conclude that spinal nerve sheath tumors in patients with neurofibromatosis type 1 are neurofibromas. In contrast, spinal nerve sheath tumors occurring in neurofibromatosis type 2 or sporadically are most frequently schwannomas. The distinct histological features of these tumors may reflect different pathogenetic mechanisms even though they arise at identical sites in neurofibromatosis types 1 and 2.     

Multiple neurilemomas in the upper extremity: a series of three cases

Neurilemomas are the most frequently arising benign nerve tumors of the upper extremity and are also called Schwannomas. Generally, they present as solitary tumors, although multiple tumors are common. Regardless of number, they are usually found on the lexor surface of the forearm and hand, and multiple tumors are almost always located within a single major nerve, its branches, or both. We present three patients who had multiple neurilemomas; two patients had tumors within a single major nerve and its branches, and the third patient had an unusual occurrence of one tumor in the ulnar nerve and a second tumor in a branch of the median nerve.     

Internal anatomy of the communicating branch between the ulnar and median nerves in the hand and its relevance to volar digital sensibility.

We studied the microanatomy of the communicating branch between the ulnar and median nerves in 26 adult cadaver hands to explain diminished sensibility in the fourth and fifth fingers we had observed in 2 patients after complete transection of the median nerve. Two new variations of the communicating branch were observed. In the first variation the communicating branch originated proximally from the third common digital nerve to distally join the ring finger ulnar digital nerve and the small finger radial digital nerve. In the second variation the ramus communicans traversed perpendicularly between the third and fourth common digital nerves with a crossover of nerve fibers.     

The frequency of digital artery resection in Morton interdigital neurectomy

BACKGROUND: Operative strategies used in resecting the digital nerve in Morton neuroma emphasize retaining the digital artery. Concern over inadvertent resection of the digital vessel has prompted many surgeons to avoid adjacent interdigital neurectomies when more than one nerve is affected. METHODS: The current study examined 674 consecutive pathologic specimens obtained after neurectomy. RESULTS: The digital vessel was identified along with the resected nerve in 39% of specimens. No adverse effect was recorded from these arterial resections. CONCLUSION: Extensive collateralization of digital vessels is hypothesized to account for the lack of adverse sequelae.     

Primary fallopian canal glomus tumors

Primary fallopian canal glomus tumor has been reported only once previously, although the occurrence of glomus body tissue in the fallopian canal was documented many years ago. Facial paresis as a presenting symptom of glomus tumors is well known, as is facial nerve invasion by glomus tumors. However, a primary fallopian canal glomus tumor that extends extratemporally to the pes anserinus is unusual. Although facial nerve grafting may be necessary for removal of some glomus jugulare tumors, the need for facial nerve grafting appears to be uniform in the patients with primary fallopian canal glomus tumors. The primary fallopian canal glomus tumors that we report did not involve the jugular fossa or the Jacobson's branch of the glossopharyngeal nerve. Both tumors did extend to the middle ear and mastoid and followed the facial nerve extratemporally. The latter features appear to typify primary fallopian canal glomus tumors.     

Tumeurs des nerfs périphériques

Peripheral nerve tumors are most often benign tumors of the nerve sheath; uncommonly they come from the nerve cells or are metastatic tumors. A precise diagnosis is required for well-adapted and effective treatment, as is good knowledge of fibromatosis diseases. In some cases, the diagnosis of the nerve tumor will lead to a diagnosis of phakomatosis. Surgical treatment must be clearly discussed, which, in case of schwannomas gives very good functional results. Primitive malignant tumors remain an unsolved therapeutic problem.